ANTIBODY The coronavirus can last at least six months and provide protection from a second infection, according to a study of health workers in the UK.
Staff at Oxford University Hospital are regularly tested, both for infections Covid-19 and for antibodies that reveal past infections.
The more antibodies a person has, the less likely they are to be reinfected.
Another separate study found that antibodies or immunity that has been formed from other types of coronavirus can also protect against Covid-19.
Antibodies ‘drop rapidly’ after being infected with Covid and are at risk of catching the virus several times. The success of the ‘herd immunity’ Covid-19 is in doubt, according to scientific studies
Infection consultant Dr. Katie Jeffery called the Oxford findings “good news” ahead of the realization of the Covid vaccine.
They indicated that people who had been infected with the virus once “provided at least short-term protection” from becoming infected again, he said.
The Oxford study followed more than 12,000 health workers, 11,000 of whom tested negative for Covid-19 antibodies.
Antibodies are formed during viral infection, preventing the virus from entering the body’s cells and attacking the immune system.
Among those without antibodies at study entry, 89 had symptomatic infections confirmed by tesseka (swab).
Meanwhile, of those with specific antibodies to the coronavirus, none had symptomatic infection during the study period.
Three people had asymptomatic Covid-19 infection despite a positive antibody test, compared to 76 people in the group without antibodies.
However, none of the three people became sick.
The results were “consistent with repeated exposure to Sars-CoV-2 that did not lead to repeated symptoms,” the study said.
The antibody studied is a type that binds to the “spike” or sharp tip of Sars-CoV-2 which causes Covid-19 infection.
It is that “spike” part that is the target of many of the vaccines currently in development. Tested staff were then followed for up to 30 weeks.
Earlier this week, a study by the British government agency Public Health England focused on T cells – another element in our immune system response to infection.
The study found in June that a quarter of workers in key or crucial sectors studied had very high levels of T cells, which recognize the Covid virus in their blood – but only about half of them had Covid-19.
The researchers concluded this immunity may exist “due to previous infection by a coronavirus other than SARS-CoV-2”, such as the common cold virus.
And people with high levels of relevant T cells “appear to be protected against Covid-19 for four months after being recruited,” whether or not they have been infected with Covid-19.
However Dr. Rupert Beale at the Francis Crick Institute research institute points out that this equates to “a very small proportion in the adult population (less than 10%, perhaps much less than 10%” that would be protected by T cells already present in the immune system.
Previous paper suggested that focusing solely on antibodies could ignore many people who are protected from reinfection by T cells – another part of the immune system response.
–
–
