Single dose of COVID-19 vaccine can help people who already had the disease

COVID-19 pandemic has put us on our toes. It feels like it’s been bothering us for a very long time and the end is not in sight yet. However, vaccines may end this pandemic rather soon if we are efficient at vaccinating people. Now scientists from UCL say that it is a good idea to vaccinate people who already had the virus, but a single dose should be enough.

Most COVID-19 vaccines are administered in two shots. Image credit: Tim Reckmann via Wikimedia (CC BY 2.0)

COVID-19 vaccination should reduce the number of daily new cases and deaths. This is why older and sick people are getting vaccines first, as well as specialists who work with a lot of people (like healthcare professionals). People who already had COVID-19 are not high on the priority list for vaccines because they already have some immunity from this disease. But maybe a single dose would help anyway?

The problem is that now we have several different variants of COVID-19. Immunity from one variant is not necessarily going to protect from other ones. This is quite worrying, because then we should be vaccinating people who had COVID-19 before. Scientists looked at the immunity responses of healthcare workers who had previously contracted Covid-19. Healthcare professionals are getting vaccinated regardless of their previous COVID-19 history, because of their high-risk working environment. Researchers found that after healthcare workers had taken their first Pfizer vaccine dose they had a significant immunity against other variants of the disease. Scientists figured this out by analysing antibodies and two types of white blood cell: B-cells, which ‘remember’ the virus and T-cells, which help B-cell memory and recognise and destroy cells infected with coronavirus.

These findings have some important implications. First of all, maybe vaccinating people who had COVID-19 is a great idea, because vaccines boost immunity and help them to gain even more protection than they have naturally. Secondly, one vaccine shot is enough – other doses should be preserved for people who do not yet have the immunity.

Professor Rosemary Boyton, leader of the research team, said: “Our findings show that people who have had their first dose of vaccine and were not previously infected with Covid-19 are not fully protected against the circulating variants of concern. Natural infection alone may not provide sufficient immunity.”

COVID-19 has many forms and natural immunity or even vaccines cannot protect from all of them. We are racing against the virus and if our vaccination process is efficient enough, we can win. People always say that they want to return to normality – this is the way we can do it. Keep the safety measures and get vaccinated when you can.


Source: UCL