An Oxford study has shown that people who have had coronavirus are likely to be immune from the disease for at least six months.
The research was conducted by University of Oxford and Oxford University Hospitals NHS Foundation Trust over a six-month period. 12,180 healthcare workers were regularly tested for coronavirus to analyse COVID-19 reinfection rates.
Antibody tests showed that 1,246 employees had already had the virus. 89 of 11,052 staff who had not had the disease at the start of the study went on to develop a symptomatic infection. However, only 3 of those who had previously been infected tested positive for coronavirus a second time.
The findings show that those who have had Covid-19 are unlikely to test positive again within six months of infection. The study also noted that those who caught the virus for a second time were all asymptomatic.
These findings mark the first large scale study of the levels of protection those infected by coronavirus have against contracting the disease again.
Previous research involving staff at the Oxford University Hospitals NHS Foundation Trust had concluded that antibody levels dropped quickly following infection. This meant individuals were potentially exposed to contracting the virus for a second time.
The study noted that the drop in antibodies was most significant in young adults. However, the findings are yet to be peer-reviewed.
Professor David Eyre, a member of the University of Oxford’s Nuffield Department of Population Health, highlighted the importance of the new research.
“We know from a previous study that antibody levels fall over time, but this latest study shows that there is some immunity in those who have been infected.
“This ongoing study involving a large cohort of healthcare workers has shown that being infected with COVID-19 does offer protection against reinfection for most people for at least six months.
“This is really good news, as we can be confident that, at least in the short term, most people who get COVID-19 won’t get it again”.
The study follows announcements of successful coronavirus vaccine trials from Pfizer-BioNTech, Moderna and AstraZeneca-Oxford. There is now optimism that subject to regulatory approval, the UK could begin its vaccination programme next month.
In the meantime, the country will exit the nationwide lockdown on the 2nd December and move back to a regional three tier system.
Sue Hopkins, one of the authors of the paper, spoke of the broader importance of the recent Oxford research:
“This study is a fantastic example of how well-structed long-term cohort surveillance can produce hugely useful results. Studies like this one are absolutely vital in helping us to understand how this new virus behaves and what the implications are for acquired immunity. This, as well as Public Health England’s SIREN study, are key to ensuring that we have the information we need to respond to the pandemic in the most effective way”.
