The common cold can provide some protection from COVID-19, according to new research led by Imperial College London, which says the findings provide a blueprint for future vaccines that could offer immunity to all variants of the coronavirus.
Since the start of the pandemic, scientists have questioned why some people are able to resist coronavirus infection despite prolonged exposure, while others are easily infected. The researchers set out to test a theory that a type of white blood cells called T cells, produced by the human body to fight the cold, could offer some protection.
"Previous infection with common cold coronaviruses — these are distantly related cousins of SARS-CoV-2 which causes COVID-19 — infection with those might induce T cells that would be able to cross-recognize and then attack the SARS-CoV-2 virus. That was the theory that we set about to test," report co-author Ajit Lalvani, chair in infectious diseases at Imperial College London, said in an interview with VOA.
The study began in September 2020 before any mass vaccination programs and before most people had been infected with COVID-19.
Scientists sampled the blood of 52 people who lived in the same household as they would someone infected with the SARS-CoV-2 virus. The sampling took place immediately after the COVID-19 diagnosis was confirmed.
Exactly half of those sampled contracted COVID-19, while the others did not.
"Those contacts who had preexisting T cells that were induced by common cold coronavirus (and which could) cross-recognize and attack SARS-CoV-2 people with such T cells didn't get infected," Lalvani said.
Current COVID-19 vaccines are designed to trigger an immune response that targets the spike proteins on the outside of the coronavirus, which are easily able to mutate and escape immunity.
"In contrast, the T cells we discovered that mediate this protection are directed against proteins in the core of the virus, internal proteins," Lalvani said. "And these proteins are much less changeable. So essentially, our findings provide the blueprint for producing a universal T cell-inducing vaccine to protect people against current and all future variants of COVID-19."
Development of such a vaccine remains some way off. Meanwhile, the report's authors emphasize that no one should rely on a common cold infection to provide immunity against COVID-19.
"Not least because the coronavirus only causes a proportion of the common cold. Maybe one-fifth or so of common colds are due to coronaviruses, and the remainder due to other types of cold-causing viruses," Lalvani said.
"And in any case, whether you've had a coronavirus common cold or not — and you'd have no way of knowing — you should still get double-vaccinated and have your booster," he said.