For some the common cold occurs as common as it gets, but on the bright side it may not be as terrible after all. Why? A latest study by ‘Nature Communications’ says that the common cold could act as a barrier against the coronavirus. Researchers from the Imperial College London found in their research that high levels of T-cells from the common cold could be the guardians shielding the body from the attacks of the virus.
However, the research says that the common cold may not be the ultimate barrier for the virus, yet it could help build immunity against the virus.
The Logic
Since one type of coronavirus causes COVID-19 infection and another type of coronavirus causes the common cold, scientists wondered if immunity to one could also protect against the other.
When a person gets a common cold, the body produces T cells that help build immunity. These T cells serve as memory banks, allowing them to recognize additional coronaviruses, such as the COVID-19-causing SARS-CoV-2.
Researchers looked at how the presence of pre-existing T cells affected the behavior of SARS-CoV-2 after an individual was infected with the novel coronavirus in this first-of-its-kind investigation.
"Being exposed to the SARS-CoV-2 virus doesn't always result in infection, and we've been keen to understand why. 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," said Dr Rhia Kundu, the first author of the study.
However, the researchers caution that assuming that a cold will always provide full protection against COVID-19 is a ‘grave mistake’, as not all colds are caused by coronaviruses.
The Experiment
The study comprised 52 participants who had been exposed to the virus after living with someone who had PCR-confirmed SARS-CoV-2 illness. To see if they had an infection, the subjects took PCR tests at the start, four days later, and seven days later.
Blood samples were taken from the 52 individuals within 1-6 days following their exposure to the virus. The researchers were able to look at the amounts of pre-existing T-cells that had been produced by previous common cold coronavirus infections and could cross-recognize SARS-CoV-2 virus proteins.
The researchers discovered that the 26 people who did not become infected had considerably larger amounts of these cross-reactive T-cells than the 26 people who did become infected. To fight against infection, these T-cells targeted internal proteins within the SARS-CoV-2 virus rather than the spike protein on the virus's surface.
Blueprint for Future Vaccines
The findings of this study could serve as a model for a second-generation universal vaccination that can protect against infection by all SARS-CoV-2 variants, including Omicron.
Instead of fighting the spike proteins that connect to human cells, T cells attack the virus's inner sections. However, many existing COVID-19 vaccines only target the spike proteins, which mutate often and produce variations like Omicron, reducing vaccine efficacy.
As a result of this research, it may be possible to produce better vaccines that better harness the action of T-cells in order to give broader and longer-lasting protection against COVID-19 and its evolving variations.
“Our study provides the clearest evidence to date that T cells induced by common cold coronaviruses play a protective role against (Covid) infection,” Professor Ajit Lalvani, senior author of the study, said.
He added, “These T cells provide protection by attacking proteins within the virus, rather than the spike protein on its surface.”
“New vaccines that include these conserved, internal proteins would, therefore, induce broadly protective T-cell responses that should protect against current and future SARS-CoV-2 variants,” Lalvani said.
"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. Instead, the best way to protect yourself against COVID-19 is to be fully vaccinated, including getting your booster dose," Dr Kundu added.
According to Dr Saad Hafeez Usmani, Consultant-Internal Medicine, Manipal Hospital, Varthur Road, “This data could be beneficial for the next steps of Covid vaccine development with a focus on internal proteins for a lasting protection as T-cells response persists longer than antibody response that fades within a few months of vaccination.”
However, Dr Usmani said relying only on this study is not advisable. “Although it’s an important discovery, due to a small sample size and no ethical diversity, it should be considered only one form of protection and to rely only on it is not advisable.”
“The best way to protect yourself against Covid-19 is to be fully vaccinated, including getting your booster dose,” he suggested.
The SARS-CoV-2 virus has evolved since its discovery, and the World Health Organization has recognized five variations as SARS-CoV-2 Variants of Concern (VOC) to date — Alpha, Beta, Gamma, Delta, and Omicron – due to their impact on transmission, illness severity, or immune escape potential. The evolution of SARS-CoV-2 is predicted to continue as the Omicron variety spreads fast over the world, and Omicron is unlikely to be the last VOC, according to WHO.
WHO asserted that for the Omicron variant, “the mutational profile and preliminary data indicate that vaccine effectiveness will be reduced against symptomatic disease caused by the Omicron variant”.
“But protection against severe disease is more likely to be preserved. However, more data on vaccine effectiveness, particularly against hospitalisation, severe disease, and death are needed, including for each vaccine platform and for various vaccine dosing and product regimens”.
However, Dr Shuchin Bajaj, founder director, Ujala Cygnus Group of Hospitals, said that a “long-term” solution is far in sight. “It is too early to label Covid-19 as the new common flu, and we still don’t know its long-term effects. Even with Omicron, we are seeing that the virus can stay in the body for longer. The previous variants have been detected in the body for as long as six months and in organs other than the lung, such as the heart and the brain. So, we will need specific vaccines for emerging variants as well,” he said.