Covid-19 Vaccine, Previous Infection and Immunity

There still remains some uncertainty about the immunity offered after the Covid-19 vaccine or previous Covid-19 infection.  The largest study looking at this is called the Siren Study.  This study looks at thousands of healthcare workers in the UK.  This will also assess the response the Covid-19 vaccine in the future.

This study looked at 6614 people who had positive antibodies using Covid-19 antibody tests. This indicates that they are likely to have had previous Covid-19 infection. In this group, they found reinfection in 44 people.  They suggest that based on this there is 83% rate of protection from reinfection if you have had Covid-19 previously.  They also found that the antibody protection after infection lasts for a minimum of 5 months on average.   There is further work to see if this last longer.  There is still no definitive indication as how long the vaccine results will last either.

It is important to note that even if you have had previous infection or antibodies, you may still carry the virus and transmit to others.  Therefore, everyone should continue to follow government guidance on preventing the spread of the virus.