Scientists believe an unlikely group of people could hold the key to solving issues that could help end the pandemic.
Further research into people who have yet to contract Covid could help create better vaccines, scientists say.
Dubbed as people with Covid ‘super immunity,’ a study published in Naturelooked at how some healthcare workers appeared to have a natural immunity against Covid-19 and continued to test negative to the virus, despite exposure.
The research was led by Leo Swadling – an immunologist Leo Swadling from the University College of London – and his colleagues.
As this study was conducted during UK’s first wave of the pandemic in March 2020, a vaccine had yet to become available.
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The study found that repeated exposure to previous coronaviruses prior to the pandemic had equipped these individuals with better T-cell reactivity. This mean they were able to fight off the genetic elements of Covid-19 upon initial infection as they were similar to previous coronaviruses.
For reference, coronavirus is merely the name given to a family of viruses which cause respiratory and intestinal illnesses in humans and animals. For example, the 2002 to 2003 severe acute respiratory syndrome (SARS) epidemic in China was another kind of coronavirus, however there are milder forms of the virus too.
A similar effect is also seen in individuals with immunity against hepatitis B, hepatitis C, and HIV and Japaneses encephalitis, the study said.
Speaking to Bloomberg, Dr Swadling said the healthcare workers showed the ability to control the virus “very quickly”.
“We were particularly interested in people who are exposed to the virus, but control it very quickly, clearing the virus before it can replicate to detectable levels and before it induces an antibody response,” Dr Swadling said. “It may help us better understand what immunity is best at protection from reinfection.”
Their research also found that “long-lived” T-cells – which stop the development of a virus – may offer better and more lasting protection than antibodies which attack a virus once it enters the body. Although previous infection and vaccines help the body produce more antibodies against a virus, this protection wanes after a certain period.
Using this information, scientists may be able to create vaccines which can create “cross-reactive” T-cells which target multiple different coronaviruses. This means the vaccines could be effective against combating new variants and offer better protection without the need for additional doses.
In January 2021, a study from the UK’s renowned Imperial College London also looked at the importance of T cells in offering protection against contracting Covid-19.
Led by a research team from the Imperial College London’s National Heart and Lung Institute, Rhia Kundu, she found that T cells from even the common cold (another kind of human coronaviruses) can give people better protection.
The research was conducted by investigating blood samples from 52 people who lived with a Covid-positive case.
“Being exposed to the SARS-CoV-2 virus doesn’t always result in infection, and we’ve been keen to understand why,” said Dr Kundu.
“We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against Covid-19 infection.”
However, vaccination was still a crucial part of protection against the virus.
“While this is an important discovery, it is only one form of protection, and I would stress that no one should rely on this alone,” Dr Kundu said.
“Instead, the best way to protect yourself against Covid-19 is to be fully vaccinated, including getting your booster dose.”