While antibodies are easy to detect from a relatively small amount of blood, such as from a finger prick, other parts of the immune system, such as T cells, require a larger blood samples and more specialised laboratory equipment to process and assess. That is because they only measure one part of the adaptive immune system. While our tests for the presence of antibodies are a helpful measure of past infections and the impact of the vaccination programme, these results are not a measure of the number of people who have protection against COVID-19.

Antibody finger-prick tests help build the picture, but they don’t tell the whole story: Then, for example, if a person gets exposed to SARS-CoV-2, their body has memory B cells and T cells which recognise the antigens on the viruses’ surface and trigger the production of antibodies to fight it. Rather than getting these ‘memory’ cells from a natural infection, a vaccination tricks the body into thinking that it has been infected when it hasn’t, so that their immune system develops these ‘memory’T cells and B cells. If someone gets exposed to the same virus again, these T and B cells (called “memory cells”) remember the old infection and rapidly multiply to fight it off without the person getting sick. It is called adaptive because each infection leads to T and B cells that are specifically tuned to that infection. T cells help the B cells produce antibodies and activate other immune defences and tell other cells to destroy the virus. This recognition comes from part of the immune system that remembers past infection, known as the ’adaptive immune system’, which consists of B cells and T cells. If our immune system recognises a viral antigen, perhaps from a past infection, then immune cells, known as ‘B cells’, will produce antibodies that bind to the virus and signal for other cells in the immune system to destroy the virus. There are several parts of the immune system that provide protection against viruses. The proteins found on the surface of the virus, called antigens, are recognised by the immune system, causing it to respond to the virus and prevent illness. Like any virus, SARS CoV-2 is made of up of two key parts: genetic material (RNA) and proteins.

Since the start of 2021, we have seen the impact of vaccination with an increasing number of people testing positive for antibodies, including after their first dose of vaccine. Before the vaccination programme, the number of people testing positive for antibodies gave a good indication of past SARS-CoV2 virus infection.

They contribute to protecting us against a second infection and prevent us getting sick. Professor Sarah Walker, Professor Jeremy Farrar and Sarah Crofts explain more about antibodies and how our immune system protects us from infection: How the immune system works:Īntibodies are made by our body after infection and after vaccination. Since April 2020 our Coronavirus (COVID-19) Infection Survey (CIS) has collected nose and throat swabs and blood samples from people across the UK to test for SARS-CoV2, the virus that causes COVID-19, and for antibodies against it. How much protection have we built against the virus as a result of natural infection and vaccination? A key question for science and health, and to successfully beat Covid-19 is

Antibody production definition