A-Z Topics



Antibodies are proteins produced in response to a specific foreign invader, an antigen. Antibodies circulate in the blood hunting for antigens they recognise. When a familiar antigen is spotted, antibodies can stop it from entering or damaging your cells. Enough of the right antibodies can often keep you from getting sick with the same virus more than once. It is too early to tell what this means for Covid 19.


Also known as antimicrobials, antibiotics are administered because they are active against bacterial infections. They kill bacteria by interfering with some aspect of their growth or metabolism. There are several different classes of antibiotic such as the penicillins, cephalosporins and carbapenems. Antibiotics are not active against common viruses such as the cold or influenza and are not active against COVID-19 and variants.

Asian Flu (1957-58)

Asian flu is the name given to the 1957-1958 influenza pandemic. Specifically, the Asian flu was a subtype H2N2 of the influenza A virus. Originating in Guizhou Province, Mainland China, it killed an estimated 1.4 million people worldwide. A vaccine was developed in the United States by Maurice Hilleman in 1957 which is reckoned to have saved thousands of lives.


Because Covid-19 was seen as a new virus by the WHO, it was considered possible that the virus could be transmitted by a person with no symptoms of the disease. Asymptomatic people have never before been treated as dangerous. This idea of contagion among symptom-free individuals contradicts what virologists and immunologists know about viruses.


Behavioural psychology

Also referred to as behaviourism, the theory that human behaviour is shaped by the environment which is employed by the Behavioural Insights Team, also known as the ‘Nudge Unit’. It has played a big role in assisting the government formulate its response to Covid-19, using the ideology of social engineering, techniques in psychology and marketing. The purpose is to influence public thinking and decision-making to improve compliance with government policy, and to decrease social and government costs related to inaction and poor compliance with policy and regulation.



‘Casedemic’ means an increase in cases of Covid 19 without any concomitant sickness or deaths. People who are sceptical of the severity of the Covid 19 pandemic claim that what we are seeing is an epidemic of positive tests, not of a real disease, hence the term ‘casedemic.’ The word did not appear until early August 2020 on Google-search and cannot be found in the Oxford English Dictionary.

Case Fatality Rate

In epidemiology, this is the proportion of fatalities from a disease compared to the total number of symptomatic people diagnosed with the disease in a particular period. Typically, the CFR is expressed as a percentage representing the measure of severity. The measurement is most often used for diseases with limited-time courses, such as outbreaks of acute infections, and can only be considered final when all cases have been resolved (either died or recovered). The preliminary CFR during an outbreak with a high daily increase and long resolution time would be substantially lower than the final CFR.


A co-morbidity is a condition pre-existing alongside another or several conditions. The combined effect of other pre-existing conditions is described as co-morbidity. Co-morbidities are considered to put a person at greater risk of having a severe illness if infected with COVID-19. Examples of such co-morbidities include cancer, obesity and respiratory disease.

Contact tracing

The identification of persons who have come into contact with an infected person in order to prevent the spread of a disease, or to learn about its characteristics and infectiousness. In an effort to contain the virus SARS-CoV-2, the NHS introduced a system whereby a person who had been in contact with an infected person is telephoned and required to isolate. Alternatively, a smartphone application can be used for the same purpose. Contact tracing has been criticised for being introduced too late, as it is not effective when the virus is widely spread, and also for its invasion of privacy.


The family of coronaviruses co-exist with humans and animals worldwide, and continuously mutate. They are seen as responsible for 10-20% of respiratory infections and generate symptoms of the common cold. Virologists believe that many infected individuals remain asymptomatic, others experience mild symptoms, whilst some develop fever and joint pains. Severe illness occurs mainly in the elderly and can be fatal, particularly in those with pre-existing illnesses.

Coronavirus Act 2020

When the Covid-19 health crisis was declared a pandemic by the WHO, governments all over the world were able to introduce emergency legislation to control the spread of the disease. The Coronavirus Act 2020 grants the UK government discretionary powers to limit or suspend public gatherings and transport, to order businesses to close, to detain individuals suspected of being infected by SARS-CoV-2, to close educational institutions and childcare premises and to postpone elections. Other lockdown restrictions, regulations and quarantine rules were made under the Public Health Act 1984.


An acute respiratory illness in humans caused by a coronavirus (SARS-CoV-2), originally identified in China in 2019 it became pandemic in 2020. The main symptoms were originally identified as a high temperature, a new, continuous cough and a loss or change to the sense of smell or taste, however, other symptoms have been, and continue to be added to the list. Although, statistically, resulting in an asymptomatic or mild infection in children and young people, the symptoms can be severe and life threatening , especially in older people (particularly those aged 80 and above) and those with underlying health conditions.


Death certification

The Government has stated that in the “emergency period of the COVID-19 pandemic” there is a relaxation of the rules concerning medical certification of cause of death. Covid-19 is an acceptable direct or underlying cause of death but doctors can certify this cause “to the best of their knowledge and belief” (without diagnostic proof). For example, if before death the patient had symptoms typical of Covid, but the test result has not been received, it would be satisfactory to give this as the cause of death. Death certificates have been seen with such wording as “presumed Covid 19”.

Diamond Princess

The Diamond Princess was a cruise ship operating around Asia and Australia. In February 2020, a case of COVID-19 was diagnosed in a former passenger who had joined the ship in Japan and left at Hong Kong. On the next voyage, 10 passengers were diagnosed with COVID-19 after which the ship was quarantined in Japan. Ultimately, over 700 passengers tested positive and 14 died.


The global spread of Covid 19 has been mirrored by the diffusion of misinformation and conspiracy theories about its origins such as 5G cellular networks and the motivations of measures taken like vaccination, social distancing and face masks. During the Covid 19 epidemic, misinformation and fake news have been an important issue generating confusion, insecurity and fear among the population. At the beginning of the pandemic the medical community played a role in making the situation even more confusing by giving, in some cases, inaccurate and sometimes contradictory indications on Covid 19.



Belonging or native to a particular country or people. In epidemiology, an infection is said to be endemic in a population when the infection is constantly maintained at a baseline level without non-pharmaceutical interventions, such as lockdowns, distancing and face covers. The baseline level is often regarded as the expected level of the disease and refers to the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area.


The WHO defines it as “the occurrence in a community or region of cases of an illness” that are “in excess of normal expectancy”. The term is used especially for infectious diseases but is also applied to any disease, injury or health-related event. The number of cases required by the WHO for an epidemic to be confirmed, and for control measures to be put in place, varies according to aspects of the population affected (type, size, density, and previous exposure to the illness).


A branch of medicine which studies the incidence and prevalence of disease, its causes, and its spread in specific populations. The results of epidemiology are used by public health officials to implement plans and policies. There are several areas within epidemiology including disease surveillance, occupational epidemiology, and clinical trials.

Essential (or ‘key’) workers

An employee who is considered to provide an essential service. During the pandemic, these workers were granted exemption from lockdown regulations, and were defined by the government as:

  • Health and Social Care: doctors, nurses, midwives, paramedics, social workers, home carers and staff required to maintain health and social care sector
  • Education and childcare: pre-school and teaching staff, specialist education
  • Public safety and national security: civilians and officers in the police, Fire and Rescue Service, prison service, National Crime Agency, national and local government including administrative occupations
  • Transport. air, water, road and rail
  • Utilities, and Communication: oil, gas, electricity, water, sewage, waste disposal, telecommunications, post and delivery
  • Financial Services: banks/building society workers and financial market infrastructure
  • Food and other necessary goods: food production, processing, distribution and sale, hygiene and medicine providers

Excess mortality

An increase in the mortality rate (percentage number of deaths in a given population) which is measured by comparing the rate with the average over a period of time. There are excess deaths every year, but the rate increases during disease outbreaks, especially among vulnerable and older people in hospitals and homes whose health is already compromised. During the Covid-19 outbreak in 2020, excess mortality increased compared to the previous year, but as 2019 had an unusually low rate, a significant increase in 2020 was expected. When the age and size of the population is taken into account, despite Covid-19, the death rate in 2020 was below average for the last 20 years.

Exit strategy

A means of terminating a policy when predetermined objectives have been met. The government and SAGE have come under increased criticism for not having a clear exit strategy to end lockdowns and restrictions. Saving the NHS from being overwhelmed by locking down the country for three weeks was the stated aim at the beginning of the crisis, but this widened to include reducing the R rate (the estimated rate of coronavirus transmission), lowering the infection rate, whether those infected were hospitalised or not, and then vaccinations – first only of the elderly and vulnerable and expanding to include the vaccination of all adults.


False positives

A test result which comes out as positive, although the patient is negative for the virus. The false positive rates for various SARS-CoV-2 tests are unknown, but the WHO has stated that the PCR-tests do produce false positives. If the false-positive rate is 1%, then one in every 100 tests administered will produce a positive result, although the patient is in fact negative for the virus. The greater the number of tests, the more false-positives there will be.

Free money

A term used for the government’s Covid-19 payment scheme. The furlough scheme pays 80% of an employee’s wages to a maximum of £2,500 a month. Originally scheduled to end on 31 May 2020, the scheme has been extended four times and is currently scheduled to end on 30 April 2021. In addition, Local Restrictions Support Grants are available for businesses in England forced to close; they receive a maximum of £3,000 for each 28-day period. Local Authorities receive funding to make grants available to businesses not forced to close but severely affected by restrictions, they receive a maximum of £2,100 for each 28-day period.


Gompertz curve

A type of mathematical model originally derived to estimate human mortality. It is widely used in epidemiology and virology to explain the behaviour of many biological processes. Researchers from Stanford School of Medicine and ShanghaiTech University demonstrated that the progression of the Covid-19 epidemic did not follow an exponential growth law even in the very beginning but, instead, its growth slows down exponentially with time. More specifically, the results irrevocably show that Covid-19 cases grew in accordance with the Gompertz function.

Great Barrington Declaration

Signed by over 700,000 ordinary citizens, over 13,000 medical and public health scientists and over 41,000 medical practitioners it advocates an end to global lockdowns with a focus on protecting vulnerable citizens. The declaration was authored by Dr. Martin Kulldorf (Professor of Medicine at Harvard University), Dr. Sunetra Gupta (Epidemiologist and Professor at Oxford University) and Dr. Jay Bhattacharya (Professor at Stanford University Medical School).


Herd immunity

Herd immunity, also known as ‘population immunity,’ is the indirect protection from an infectious disease that happens when a population is either immune through vaccination or immunity developed through previous infection. The percentage of people who need to be immune in order to achieve herd immunity varies with each disease. For example, for measles it requires about 95%, for polio about 80%. The proportion of the population that must be vaccinated against Covid 19 to begin inducing Covid 19 herd immunity is not known.

Hong Kong Flu (1968-69)

A global influenza pandemic which killed up to four million people worldwide. The outbreak originated in China in July 1968. The virus was highly contagious and spread through the United States in the autumn of 1968, reaching western Europe by the end of December. Those most at risk of succumbing to the virus were infants and the elderly. Lockdown measures were not considered during this pandemic. The H3N2 virus which caused the pandemic is still in circulation today.


A medication used chiefly to prevent and treat malaria,but also a treatment for rheumatoid arthritis and lupus. During the SARS pandemic in 2003,this treatment was shown to have inhibitory effects either before or after exposure to SARS-CoV, suggesting both prophylactic and therapeutic advantage. Throughout the Covid-19 pandemic, views on its efficacy have caused controversy.



Innate immunity is the ability to resist a particular disease, either through the activities of specialized blood cells or antibodies produced by them in response to natural exposure. Humans have two other types of immunity; adaptive which develops throughout our lives when exposed to a disease or when we are immunized, and passive which is the transfer of antibodies from a mother to her baby via the placenta or breast milk.


The ability of a disease to be passed easily from one person to another, especially through air or water. Current evidence suggests that the main way the virus which causes Covid 19 spreads is by respiratory droplets among people who are in close contact with each other. Individuals infected with Covid19 (SARS-CoV-2) are most likely to be highly infectious a few days before symptoms start and the following five days.

Infection Fatality Rate

The proportion of people infected with a disease who die from the disease. The infection fatality rate (IFR) of SARS-CoV-2 has been unknown since the start of the outbreak. However, data gathered since then has shown the IFR to be much lower than previously estimated. A large study conducted by Professor John P. A. Ioannidis for Stanford University found the median IFR to be 0.23%, with 99.77% of people surviving the virus.


A viral infection, commonly known as ‘the flu’ w,hich attacks the respiratory system (nose, throat and lungs). Influenza circulates every winter and kills an estimated 650,000 people each year. There were four major influenza pandemics in the 20th century: Spanish flu (1918), which killed up to 100 million people, Asian Flu (1967) and Hong Kong Flu (1968), which each killed up to four million people, and Russian Flu (1977), which killed an estimated 700,000 people. No lockdown measures were implemented during these pandemics.

(Social) Isolation

Social isolation describes a state of being cut off from normal social interactions which can be triggered by factors such as loss of mobility, health issues or externally imposed restrictions. Isolation can involve staying at home for prolonged periods, without access to services or community involvement, with little or no communication with friends, family, neighbours or acquaintances. It frequently results in loneliness. In addition to declining physical health, the detrimental emotional effects of social isolation include increased stress, anxiety, negative emotions and depression. If not alleviated this may lead to self-harming or suicidal tendencies. Vulnerable individuals are at most risk.


Judicial Reviews

A process or court case where a judge or judges examine the lawfulness of a government decision. This can be the decision of a central government department, another government body such as a regulator, a local authority, or certain other bodies when they are performing a public function. There are three main grounds for judicial review: illegality, procedural unfairness, and irrationality.


Legal challenges

To mount a legal challenge means to bring a formal action, proceeding or litigation before any court, tribunal, arbitration panel, or other judicial, adjudicative or legislation-making body, which seeks to challenge the validity and lawfulness of an action taken by an authority. It is a complex, time consuming and very costly process requiring expert legal advice and support. A number of legal challenges have been mounted by individuals, businesses and organisations around the world against governments and other authorities in relation to lockdown policies or individual measures.


The modern use of the term ‘lockdown’ originally referred to a state of isolation instituted as a security measure, particularly the confining of prisoners to their cells usually in order to regain control during a riot. Then in 2006 a USA political document ‘Targeted Social Distancing Designs for Pandemic Influenza’ (2006) by Robert J. Glass, a complex-systems analyst with no medical training or experience, presented a theoretical model-based proposal for its use in infectious disease management. When the SARS-CoV-2 virus broke out in China in 2019, China’s Communist Party implemented this unique, untested practice for controlling the spread of infections. Most countries copied China, rapidly imposing restriction policies universally preventing citizens of all ages from freely entering, leaving or moving around buildings and locations, accessing services or operating businesses, mixing with others, or travelling freely due to the presence of an infectious disease.

Long Covid

‘Long covid’ is the term that is used to refer to people who have multiorgan symptoms after Covid 19. They range from a cough and shortness of breath to fatigue, headache, palpitations, chest pain, joint pain, physical limitations, loss of appetite, depression, feeling sick, diarrhoea and insomnia and affect people of varying ages. Long-term symptoms do not seem to be linked to how ill the person was when they first caught Covid 19. The health watchdog NICE defines long covid as lasting for more than twelve weeks. This applies to around one in ten people. Experience suggests that most symptoms should go within three months while tiredness may last up to six months, but this does not apply to everyone.



A device (face covering) worn over the nose and mouth, in order to provide protection to others. Masks have been mandatory in the UK in indoor public settings since July 2020 Their purpose is to reduce the likelihood of transmitting Covid19 (SARS-CoV-2) via respiratory droplets .


Another coronavirus variant emerged in the Middle East in 2012 and caused life-threatening disease with an even higher fatality rate of more than 30%. But contagiousness of the virus was low and the outbreak was rapidly brought under control.


An epidemiological model is a mathematical representation of the transmission dynamics of infectious diseases, using collected statistics or assumptions along with mathematics to measure the efficacy of potential control measures, for example lockdowns and face cover mandates. The model provides estimates of the future magnitude, duration and geographical extent of an outbreak.


Nightingale Hospitals

These NHS hospitals were 7 temporary, critical care hospitals established by NHS England as a response to the Covid 19 pandemic. The extra capacity offered by these temporary hospitals was seen as vital in ensuring the NHS did not become overwhelmed. The Nightingale Hospital London was first to open in April 2020. Six more were opened by May in various locations around England .They had all been placed on standby or repurposed by July 2020. Nightingale hospitals are named after Florence Nightingale: born 1820, a statistician, nurse and the founder of modern nursing.

Nosocomial outbreaks

Infections acquired in health and social care settings, for example hospitals and care homes.



A body with abnormal or excessive fat accumulation that presents a risk to health, leading to the development of other medical conditions. Fat is usually visible externally but it may also be an internal accumulation around key organs. A body mass index (BMI) over 30 is classed as obese. It is normally caused by excessive consumption of food and drink combined with inadequate exercise. It is a common problem in the UK, estimated to affect a quarter of adults.



A pandemic is defined as an epidemic of an infectious disease that occurs worldwide, or over a very wide area, crossing international boundaries and affecting a high proportion of the population. By definition, a true pandemic causes a high degree of mortality (death). The word “pandemic” comes from the Greek “pan-“, “all” + “demos,” “people or population” = “pandemos” = “all the people.”

Peer review

A process whereby articles for publication are assessed on three common criteria, namely, ‘quality’, ‘relevance’ and ‘importance’ by scholars in the same field. It is a central part of the publication process for medical journals, providing feedback and critique on content which can advance the field of science


The UK government’s petitions website enables British citizens and UK residents to create or sign a petition that asks for a change to the law or government policy. 10,000 signatures will generate a response from the government and, after 100,000 signatures, a petition is considered for debate in Parliament.

PCR tests

A genetic amplification technique invented by the late Dr Kary B Mullis. The polymerase chain reaction (PCR) test detects fragments of genetic material that could be from a specific source such as a virus. It is being used to identify people with SARS-CoV-2, the coronavirus that causes COVID-19. The test has provoked conflicting claims on its efficacy, as it does not provide a medical diagnosis, and relating to the Cycle Threshold (CT value), at which the genetic material in a sample is amplified.

Positive Case

The definition of a ‘positive case’ rests on the result of the PCR Test or Lateral Flow Test (LFT), identified by taking nasal and throat specimens from people and sending these to laboratories around the UK to be tested. If the test is ‘positive’, this is referred to as a lab-confirmed case of SARS-CoV-2, the coronavirus causing Covid-19.

Post Viral Syndrome

Can occur after a person experiences the effects of a virus, developing even after seemingly simple bouts of the flu or the common cold, and now reported following a Covid-19 infection. The effects can include aches and pains across the body, headaches, sleep disturbance, depression, a general feeling of being unwell. Symptoms have been likened to chronic fatigue syndrome.


In academic publishing, a preprint is a draft of a scientific paper that has not yet been published in a peer-reviewed scientific journal. An increasing number of online platforms are enabling scientists to share their research before it has undergone peer-review.

Public Health Act 1984

The primary piece of legislation used to address public health emergencies. The Act granted powers to detain individuals suffering from disease. In 2008 the Health and Social Care Act amended sections of the 1984 Act to include additional internal provisions and international border controls. The 1984 Act was updated in 2010 granting new, extended powers and duties to local authorities to prevent and control risks to human health. The 1984 Act (amended) includes sanctions and fines for non-compliance. It incorporates provisions of the World Health Organisation’s International Health Regulations. It also permits the introduction of further regulations. Section 13 grants the Secretary of State for Health the authority to create regulations through statutory instruments to control disease in England and Wales without going through the normal parliamentary approval process. The latter power led to the introduction of the Health Protection (Coronavirus) Regulations 2020.



Quarantine separates people or animals from others and restricts their movement outside a designated place of isolation for a specific period of time when they were either exposed, or suspected to have been exposed to a contagious disease, to see if they become sick. It is a method of control to prevent disease from spreading.



The ‘effective reproduction number’, a way of measuring an infectious disease’s capacity to spread. The R number signifies the average number of people that one infected person will pass the virus to, based on the PCR test. An R value greater than 1 is when infections are deemed to be spreading uncontrolled through a population.


Reinfection is where a specific pathogen successfully invades a body more than once on completely separate occasions following recovery from or superimposed on a previous infection of the same pathogen. The subsequent disease may be equal to, milder, or more severe than the initial one. With regard to coronaviruses this is an extremely rare event. It is distinct from a resurgence where a residual pool of pathogens remains in the body after symptoms have passed, to re-emerge and multiply later when conditions become favourable.

Respiratory diseases

Respiratory diseases affect the airways and lungs, including a variety of conditions such as asthma and chronic obstructive pulmonary disease (COPD), lung cancer, and infections such as pneumonia and influenza. Respiratory infections are usually common among elderly people and those with a weak immune system. Hospital admissions due to respiratory conditions make a significant contribution to the winter pressures faced by the NHS.

Risk assessment

A quantitative risk assessment is an objective probability estimate based upon known risk information applied to considered circumstances. It is used in situations of high risk or of public concern where consequences can be severe and/or widespread, such as during a pandemic. There are specialist risk assessment tools for use with serious infectious diseases and epidemics. A risk assessment is a careful examination and recording of all the known and potential hazards that are likely to or could cause harm. Levels of risk are assigned to each of those harms including probability ratings. The assessment records measures for each hazard, monitoring measures and timescale. It should include a cost benefit analysis. Risk assessments detail health surveillance measures with priorities – matched against a valid technique for disease identification, incidence and location recording. The final section should incorporate a progressive risk reduction plan, with proposed timescales.

Risk factors

In health terms a risk factor is a practice, habit, or environmental factor rendering an individual more likely to develop a particular medical condition, infection or disease. It can apply to exposure, susceptibility or response to a causative agent. General risk factors include for example crowded conditions, poor hygiene, poor ventilation, lack of healthcare. Personal risk factors putting people at higher risk of serious disease or even death from Covid-19 include those aged over 75 – especially if they already have one or more particular medical conditions, are undergoing certain cancer treatments, are obese, or have one of the conditions listed by health authorities such as diabetes, or severe lung, heart, spleen or kidney disease. Those individuals are at high risk (clinically extremely vulnerable).



This coronavirus variant (known as ‘SARS’) appeared in 2003, causing severe respiratory illness and having a high fatality rate of approximately 10%. It was not highly contagious and its spread was contained through conventional isolation measures. 774 deaths were registered worldwide.


In December 2019, a large number of respiratory illnesses were recorded in Wuhan, China, a city of 10 million inhabitants. Patients were found to be infected with a novel coronavirus, which was given the name SARS-CoV-2. The respiratory disease caused by this was designated COVID-19.

Scientific method

This is an empirical method of procedure that has characterized natural science for at least 3 centuries. It involves systematic observation, gathering and collating data, measurement, and experiment, and the formulation, testing, and modification of hypotheses. A hypothesis is a suggested solution for an unexplained occurrence that does not fit with current accepted scientific theory. Results of the procedure are analysed and interpreted critically to either support or contradict the hypotheses. This is called falsifiability and testability.


A term often used to specify infectious diseases that cause outbreaks at particular times of the year. Factors such as temperature and humidity, and human behaviours during the summer and winter months, can interact with changing levels of population immunity to influence how common a virus infection is within the community at different times of the year.

Second wave

A descriptive term to explain the cycle of the rise and fall of virus infections, as in the Spanish flu pandemic of 1918 and recently with the SARS CoV -2 pandemic. A first wave could be said to have ended when cases have fallen substantially. The start of a second wave would see a sustained rise in infections before they decline as the ‘wave’ falls.

Severity of Covid-19

Criticism of pandemic measures is connected to the problem of severity because it is assumed that Covid 19 is a disease of greater severity than evidence allows. Most people infected will show either no symptoms at all or experience mild to moderate illness. They recover without requiring special treatment. People with underlying problems like cardiovascular or respiratory disease are likely to be more susceptible to infection (sometimes picked up in hospital), which may then become a contributory cause of death.


People identified as being ‘clinically extremely vulnerable’ are advised by health agencies or their medical practitioner to shield themselves. This is because they are at high risk of serious illness or even death if they caught a particular disease, such as Covid-19. Shielding is achieved by staying at home, except to take exercise or attend medical appointments, whilst reducing all contact with any other people to the absolute minimum. During shielding official guidance also recommends following enhanced precautions for a period of time, particularly when infections in the local community are known to be prevalent.

Symptoms of COVID-19

The main symptoms are a high temperature (37.8 degrees c or above) or a new continuous cough, or a loss or change to the sense of smell or taste. Other symptoms can sometimes be fatigue, headaches, other aches and pains, sore throat, shortness of breath. It takes five days on average from the moment of infection for symptoms to show but may take up to fourteen.



Play an important role in the ability of the immune system to protect against many viral infections as they have what is called ‘memory ‘. Studies of T cells suggest they might protect some people newly infected with SARS-CoV-2 by remembering past encounters with other human coronaviruses. This could explain why some people seem to fend off the virus and may be less susceptible to becoming severely ill with COVID-19.

Test & Trace system

This involves making a screening test rapidly available to those who experience potential symptoms. Those with positive results are instructed to isolate (quarantine) themselves. A contact-tracer interviews them to find out who they might have exposed while infected. Those who spent more than 15 minutes in close proximity to the infected person are prioritised. Contacts are instructed to self-isolate. The model is that if a system is quick, efficient and effective, the chain of transmission is broken.


The RT PCR is the main test in use for SARS-CoV-2 (real time polymerase chain reaction genetic amplification test). It uses nucleic acid testing technologies that search for fragments of genetic information – RNA. It is a complex and highly specialised process that requires a strict set of protocols and procedures. Contamination at any stage drastically changes results. A cycle of binding and copying repeated above 30 cycles also dramatically increases false positive results. The test does not indicate active infection by a replicating virus, i.e. confirm a case of the disease.

A simple Lateral Flow test detects viral proteins (antigens) from the SARS-CoV-2 virus in respiratory samples. If the target antigen is present in sufficient quantity, the kit will generate a visual signal. This test can detect people with higher viral loads without the performance of complex laboratory processes, and can provide results in approximately 30 minutes. Serological tests offer an alternative approach for detecting SARS-CoV-2 infection by measuring circulating antibodies in the blood. These antibody tests can help identify people who may have been infected with the SARS-CoV-2 virus or have recovered from the COVID-19 infection.

Three tier system

System introduced by the UK government to combat rising cases of coronavirus in October 2020. Specific geographical areas have interventions according to a Covid alert level, ranging from medium in Tier 1 to very high in Tier 3. Restrictions, for example, on socialisation, business operation, or travel, would be increased when a region was moved up a tier.


With respect to viruses, transmission can occur from person to person through sneezing, coughing, speaking and from touching objects which have become contaminated with an infective organism, such as telephones, keyboards, or door handles. SARS-CoV-2 is presumed to be transmitted largely in aerosol form rather than respiratory droplets.


Currently, treatments rest on therapeutic drugs and newly developed vaccines. Some existing drugs, for example, the steroid medication dexamethasone, have been found to save the lives of severely ill patients in hospital. Anticoagulants have demonstrated their value for patients who develop blood clots. Research continues on a range of antiviral drugs as potential treatments, such as those used to treat HIV, the virus connected with AIDS.


Underlying cause of death

As defined by the WHO, it is “the disease or injury which initiated the train of morbid events leading directly to death”. WHO guidelines state that “COVID-19 should be recorded on the medical certificate of cause of death where it is assumed to have caused, or contributed to death, i.e. COVID-19 is the underlying cause of death”. An example would be someone who has developed pneumonia as a result of COVID-19 and dies from acute respiratory distress.



A vaccine uses a small part of a virus to stimulate the immune system, so that one develops protection from that virus without becoming seriously ill. Vaccinations are normally carried out by injection of a vaccine containing a microorganism or virus in a weakened or killed state, or proteins or toxins from the organism. Inoculation is slightly different in that it achieves the same result using un-weakened live pathogens; some attenuated live vaccines are given orally, e.g. for polio. Many coronavirus vaccines employ newly emerging messenger RNA technology, which teaches the body’s cells how to make a protein—or piece of a protein—that triggers an immune response. Protective effects usually take several weeks to develop.


A ventilator takes over the body’s breathing process when disease has caused the lungs to fail, giving the patient time to fight off the infection and recover. It may be invasive as in intubation when a tube, connected to a ventilator, is inserted through the mouth and then into the airway. Non–invasive ventilation is where a mask is placed over the nose and mouth with no tube for the airway.


Airborne transmission of viruses can happen when people breathe in small viral particles (aerosols) in the air after someone with the virus has occupied an enclosed area. The longer people spend together in enclosed areas, the greater the risk. Good ventilation, such as window opening in indoor settings, has been advised by the government to mitigate potential transmission.


A subfield of microbiology, studying submicroscopic particles of genetic material contained in a protein shell, and how these viruses infect and exploit host cells for reproduction. It also includes the effect of viruses on physiology and immunity, the diseases they cause, how they are isolated and cultured, and their use in research and treatment.


Three key nutrients are vital to effective functioning of the immune system: vitamin C, vitamin D and zinc. Vitamin C is an antioxidant, protecting cells against reactive oxygen species generated by immune cells to kill pathogens. Zinc is crucial for normal development and function of cells mediating nonspecific immunity such as neutrophils and natural killer cells. Vitamin D is not only important for bone and cardiovascular health, it enhances the pathogen-fighting effects of monocytes and macrophages (white blood cells) that are important components of the immune defence system, and decreases inflammation, which helps promote immune response. There is increasing evidence that taking daily vitamin D supplements of around 1,000 iu’s during the winter months provides some protection from coronaviruses.


Weight (as a factor)

Excess weight is a risk factor for a range of chronic diseases such as Type 2 diabetes, heart disease, various cancers and since 2020, Covid- 19. Evidence suggests it is associated with an increased risk of hospitalisation, advanced levels of treatment (including mechanical ventilation or admission to intensive or critical care) and death. The risks seem to increase progressively with increasing BMI above the healthy weight range.


City located in Hubei Province in China, population over 11 million. SARS CoV-2 is said to have originated in Wuhan but how and where in the city this occurred is still under investigation. Wuhan was placed under a 76 day lockdown on January 23rd 2020 to contain and suppress the virus, a method of containment which has then been implemented by many other countries.


Zero Covid

A strategy to keep transmission of the virus as close as possible to zero and ultimately to eliminate it. This approach is also known as ‘Find, Test, Trace, Isolate and Support.’ Proponents argue that it is preferable to allowing communities to acquire immunity or resistance over time.