What immune imprinting means for the future of COVID-19 vaccines

 One of the greatest success stories of the pandemic has been the development of mRNA vaccines. However, 2 years into the pandemic, many people’s immune systems are no longer naive to the virus, which has led to questions about how vaccines could and should evolve in the future.

When AstraZenecaTrusted Source, Pfizer, and Moderna started to recruit participants for their first COVID-19 vaccine trials in the spring and summer of 2020, they had to find people who did not think they had previously been infected with SARS-CoV-2, the virus that causes COVID-19.

Pharmaceutical companies took this measure for a number of reasons — for example, the world had little idea how much previous infection with SARS-CoV-2 might protect against future infections.

Without this information, it was difficult to evaluate how much of the protection discovered in the trial was due to the vaccine or to previous exposure to the virus. This presented some challenges.

In fact, in areas heavily impacted by the virus in the first wave, the requirement to recruit participants with no previous infection was met with some initial reactions of disbelief.

Community testing had not been in place for months in many places, some people would have had asymptomatic infections, and it is also likely people had COVID-19 before they understood it was circulating in their region.

And of course, no trial participants had, in the beginning, received any other form of COVID-19 vaccine as they did not yet exist.

Research has since shown that previous SARS-CoV-2 infection alongside vaccination offers the strongest protection against future infection, that mixing and matchingTrusted Source vaccines works, and that immunity from COVID-19 wanes with time.

Our understanding of the virus has improved. We know how it spreadsTrusted Source, how to protectTrusted Source against it, and how to treatTrusted Source the disease it causes. Yet, at the same time that this body of knowledge has grown, our actual bodies have changed in how they might respond to a SARS-CoV-2 infection.

Source:Medical News Today