Understanding how some people naturally resist Covid infection, despite clearly being exposed to the virus, could lead to better vaccines, say researchers. A team at University College London said some people had a degree of Covid-immunity before the pandemic started. Upgrading vaccines to copy this protection could make the jabs even more effective.
Scientists closely monitored hospital staff during the first wave of the pandemic – including taking regular blood samples. Despite being in a high-risk environment, not everyone in the study came down with Covid. The results, published in the journal Nature, showed that around 10% of those people managed to avoid the virus. They had signs of being exposed, but never had symptoms, never tested positive and never developed Covid-fighting antibodies in their blood.
Part of their immune system was somehow able to get on top of the virus before it managed to take hold – what’s known as an “abortive infection”. Blood samples showed these people already had (as in before the pandemic) protective T-cells, which recognise and kill cells infected with Covid. Their immune systems were already “primed” to fight the new disease, as these T-cells were able to spot a different part of the virus than the bit most of the current vaccines train the immune system to find.
Healthcare workers that were able to control the virus before it was detectable were more likely to have these T-cells that recognise the internal machinery before the start of the pandemic. These internal proteins are very similar in all related species of coronavirus, including the ones that are widespread and cause common cold symptoms. It means targeting these proteins with a vaccine could give some protection against all coronaviruses and new Covid variants. Current vaccines are doing an excellent job of preventing people from becoming severely ill, but are not as good at stopping them catching Covid.
By including these T-cells, they might be able to protect against infection as well as disease, and they could be better at recognising new variants that arise. While nearly everyone will have caught these common cold coronaviruses, not everyone will have developed the right kind of protective T-cells. It may be that healthcare workers are more regularly exposed to the viruses through their work and that is why some of them had protection. Hopefully this study will lead to further advances in vaccine development. click full source.
Coincidently, it was announced today that it will become compulsory for frontline NHS staff in England to be fully vaccinated against Covid. Sajid Javid told MPs that he expected to set a deadline for the beginning of April to give 103,000 unvaccinated workers time to get both jabs. More than 93% of NHS frontline staff have had their first dose and 90% are fully vaccinated. Interestingly, this 10% who are unvaccinated is a similar proportion who are “immune” to covid, and whether or not it is a sensible policy to sack all unvaccinated staff next April is a moot point. Time will tell.