The impact of detectable anti SARS-COV2 antibody on the incidence of COVID-19 in healthcare workers

In this study, we will recruit staff working in healthcare organisations who will be followed for a year and study their immune response to the virus causing COVID-19, called Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV2). We will do this by collecting data on their history of COVID-19 infection and any new symptoms.  All participants enrolled into the study are being asked to have a regular nose swab or a combined nose and throat swab (depending on local decision) every other week to detect mild cases or cases who do not have symptoms. This is the main test that is currently used to detect and diagnose infection by looking directly for the virus in the nose and throat. Once the infection is cleared, we cannot detect the SARS-CoV2 virus in samples. Therefore, we will also ask these individuals to have blood samples taken every other week to determine whether they have antibodies to the infection. The frequency of swab tests and/or blood tests may be changed to between 1 and 4 weekly tests.  This will depend on national and local epidemiology, study retention, feedback and results. These blood samples allow the previous infection to be detected as the response to infection in the body is to produce small particles in the blood called “antibodies”. It takes up to 4 weeks to make enough antibodies to fight the infection. But once someone recovers, antibodies stay in the blood at low levels and this may help prevent us from getting infected with the same infection again. However, for SARS-CoV2 infection, we do not know yet if the detection of specific antibodies is a correlate of protection  from future infection. Through this study we will provide this very important information which will help to understand the future impact of COVID-19 on the population