What are the COIVID19 tests?

What are the COIVID19 tests?

by Philip Ingram MBE

Some see a perceived lack of testing as the latest stick to beat the government up with the current COVID-19 crisis. The perception that is being left with the general public and with healthcare workers is that testing will provide some magic solution to the crisis.  The reality is, being blunt, it won’t; being more accurate, each test has its strengths and weaknesses and no one test is the complete answer, they will only help our understanding of the spread of the infection and help keep us safer.

The current test, which is the one being scaled up, is an ‘antigen’ test. Antigens are molecules capable of stimulating an immune response in the body and that immune response is the start of the production of antibodies.

The antigen test requires a swab to be taken, usually from the back of the throat.  That swab then needs to be sent to a laboratory where the antigen is scientifically amplified and compared with a reference to see if it is what they are looking for.  This test, called the Polymerase Chain Reaction (PCR), often referred to as real-time PCR (rt-PCR), or the quantitative PCR (qPCR) test, requires trained laboratory technicians, specialist equipment and time for each test, as well as an administrative burden matching tests to results and informing individuals of results.

The current PCR test is an excellent technology but leaves a window as it misses some early cases, at times not detecting infection until a period post symptoms, even though the person can be highly infectious during that time. The test is also manpower and equipment limited, needing people to take samples, technicians and scientists to process and interpret the tests and staff to deliver the results.

Of course, a negative test one day does not mean the individual could not become infected the next day, and this is why it is essential the complimentary Antibody test is further developed and rolled out to identify who has had the infection.

This is a much simpler test using a sample of blood taken from a finger pin prick and it is then put into a device like a pregnancy test kit, but the chemistry on the test stick is designed to look for antibody.  Antibodies (sometimes called immunoglobins (IgM and IgG)) are proteins produced by the body over the course of a week or two in response to an infection and are there to fight the infection. Each antibody is designed to recognise a specific part of the cause of the infection (the antigen), lock onto it and stop it replicating thereby fighting the infection.

With the antibody test, a solution is added, and the blood sample moves up the test paper stick, interacting with the chemistry on the stick and giving an indicator that the antibody is present.  This will tell someone that they have had the COVID-19 disease in some form and only takes a few minutes to carry out. It does not indicate early infection or necessarily that an individual currently has the infection.

There are other tests currently being offered to the fight against COVID-19 that will complement the PCR antigen and the antibody test. This test is similar in its physical form to the antibody test, but the chemistry is very different.  It detects a key very early marker of the activation of the immune system in the body produced from the very early stages of the infection. This happens as the infection enters the body and is active as the body produces certain ‘help’ molecules. A marker that has been identified, following a great deal of research activity into HIV and earlier SARS infections is called neopterin.

The neopterin test does not specifically identify that an infection is COVID-19, but it does detect that someone is suffering from an activation of their immune system and, as such can detect infection at a much earlier stage in the disease than any of the other tests. It is a very simple to use and understand lateral flow test (as a pregnancy test) and can be used and interpreted by health workers and the general public, requiring no specialist support. It is projected to be non-invasive by using only a small sample of saliva, with the test results showing a positive result with a red line in a few minutes only if the individual is suffering a current viral infection.

This new test is not yet part of the governments offering but would complement the other two allowing the resource and time-consuming PCR test to be used only on those who have a positive indication of a viral infection and, critically, detecting those that are too early in the course of infection to be detected by the PCR or antibody test. It could also be used much more frequently as part of a wider screening programme as it can be self-administered, self-interpreted and produces rapid results and allow more informed self isolation, thereby reducing cross infection, potentially dramatically.

What is important is that the strengths and limitations of each type of test are known and understood and that a range of complimentary tests are available to maximise the collection of results that will rapidly let the health system and public understand the risks.

This article was written by Philip Ingram MBE with the assistance of Professor Colin Self BSc, MB, BChir, PhD, DSc, FRSC, FRCPath who has developed the Neopterin test. Please use the contact us page if you want further details.

Where did COVID-19 come from?

Where did COVID-19 come from?

Where did COVID-19 come from?

Here conspiracy theories abound, as the reality is the origin of SARS-CoV-2 is only a scientific assessment. However, based on over 50 years research into coronaviruses and that the international scientific community is quick at checking and commenting on all of the relevant works and studies in the scientific community, their current assessment is probably accurate; it is certainly extensively peer reviewed.

The World Health Organisation (WHO) situation report of 21st January 2020 said that on 31st December 2019, the World Health Organisation’s (WHO) China office heard the first reports of a previously unknown virus behind a number of pneumonia cases in Wuhan, a city in Eastern China.

On 11 and 12 January 2020, WHO received further detailed information from the National Health Commission China that the outbreak is associated with exposures in one seafood market in Wuhan City.

In February nature magazine reported that, “Chinese scientists suggested, on the basis of genetic analyses the prime suspect was the scaly ant eating pangolin.  However, it then went on to say that scientists have now examined that data and say that although the animal is still a contender, the mystery is far from solved.

Other animals that are known as host of various coronavirus strains are Bats and they, like the Pangolin, were sold live in the Wuhan market.  MERS and SARS were originally corona viruses hosted on bats, so it is now thought that they are the most likely contender.

Apportionment of its source is made slightly more conspiratorial by the fact that Wuhan is the site of China’s only facility designated at Biosafety Level 4 (BSL-4) and is known as the Wuhan Centre for Disease Control (WHCDC).  It was constructed in 2004 following the SARS emergency to conduct research into countering such viruses.  Level 4 facilities are designed to stop the escape of even the smallest particles, so accidental escape is highly unlikely. Despite sensational speculation in some press circles, there is no evidence in the scientific community that the COVID-19 disease is a result of WHCDC activity.

What is COVID-19

What is COVID-19

The next question has to be, what is CoronaVirus and what is COVID-19?  

According to the Centre for Disease Control and Prevention in the US (CDC), coronavirus is the name for a family of viruses that were first identified in the 1960’s.  They are named for the crown-like spikes on their surface (envelope) and there are four main sub-groupings known as alpha, beta, gamma, and delta.

People around the world commonly get infected with some human coronaviruses and in recent years it has been identified that coronaviruses that infect animals can evolve and jump the species gap to humans. Three recent examples of this are; severe acute respiratory syndrome, or SARS (SARS-CoV-1), Middle East Respiratory Syndrome, or MERS which were both identified as beta viruses and now we have coronavirus disease 19 or COVID-19 which has been designated as a novel corona virus, i.e. it doesn’t fit into any already known category and therefore any immunity to other types of coronavirus that is present in a species can be bypassed by this strain. The name of the virus that causes COVID-19, the disease, is Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2).

Comment: Much is already known about coronaviruses, about their protein makeup, their genetic coding, their transmission, their strengths and their weaknesses, there has been over 50 years research into them already and SARS and MERS have given recent impetus to the scientific community.  SARS-COV-2 is closely related to SARS-COV-1 which emerged in 2002. Therefore, the scientific fight against COVID-19 disease is not from a standing start, it is from a position of many years research. Comment Ends.

What is a Virus

What is a Virus

What is a virus?

The microbiological society describes a virus as the smallest of all microbes. With some, they are so small that 500 million could fit on to the head of a pin. They are unique because they are only alive and able to multiply inside the cells of other living things. The cell they multiply in is called the host cell.

A virus is made up of a core of genetic material, either DNA or RNA, surrounded by a protective coat called a capsid which is made up of protein. Sometimes the capsid is surrounded by an additional spikey coat called the envelope.

Under a process called Lysis, virus particles burst out of the host cell into the extracellular space resulting in the death of the host cell. It is this that causes the damage to the host organism, and the symptoms experienced, when many cells are killed. Once the virus has escaped from the host cell it is ready to enter a new cell and multiply.

An organism, if exposed to the virus or a similar version may have a degree of immunity as it has the genetic pattern to develop antibodies to fight the viruses and restrict their spread. The danger is when a novel virus is discovered, as organisms will have no pre prepared defences to these.