COVID Quickly, Episode 21: Colds Build COVID Immunity, and the Omicron Vaccine Delay | Scientific American - Josh Fischman & Jeffery DelViscio, 60-second Science (transcript):
January 19, 2022 - "From early in the pandemic, its been clear that not everyone is equally vulnerable to SARS-CoV-2, the coronavirus that causes COVID. Some people get really sick, while others have mild symptoms or none at all. And this was true before any of us were protected by vaccines. Overall about 80 percent of infected people get a mild illness. The virus is so wildly infectious, though, that the 20 percent of serious cases have been a global catastrophe.
"But in people who don’t get very ill — what’s protecting them? We hear a lot about neutralizing antibodies, but this is a new virus to us. You don’t get antibodies until after you’ve been exposed or vaccinated.
"It turns out some people might be getting help from another part of the immune system — T-cells, which were triggered years ago by exposure to different but related coronaviruses. These microbes have been with us forever, and they cause sneezing and runny noses: the common cold. The cold coronavirus and the pandemic coronavirus are distantly related. But they do share similar proteins. Early in the pandemic, scientists noticed that T-cells that reacted to the cold virus also reacted to the pandemic virus. These are called cross-reactive T-cells. But since researchers saw this in test tubes, they had no idea what this meant for immunity in real life.
"Ajit Lalvani, an infectious disease physician at Imperial College London, decided to find out. England has a really good contact tracing system. It allowed Lalvani and his colleagues to find 52 people who lived with individuals who tested positive for COVID. These 52 started out negative themselves. Within about 3 days, half of that group, or 26, turned positive. The other 26 stayed negative.
"Taking a closer look at the negative people, who didn’t get COVID, Lalvani’s team found that 7 of them had a lot of these cross-reactive T-cells. None of the people who got COVID had such cells. Zero. Lalvani told me this is a very substantial protective effect, and his team just published the results in the journal Nature Communications. The T cells, primed by the older cold virus, recognize the new pandemic virus because it has those similar proteins, and they work to fight it off.
"Immunologist Alex Sette, from the La Jolla Institute for Immunology, told me he thinks this research is on the right track. Other studies have linked recent exposure to these cold viruses with less severe COVID, says Sette, who was not involved in Lalvani’s work. Research has also tied pre-existing T-cells to a stronger immune response to a COVID vaccine....
"T-cells ... point to new targets to add to second-generation vaccines. The proteins these T-cells reacted to went beyond the well-known spike protein at the heart of the first-gen shots. The cells respond to other proteins called N and O-R-F, for instance. Adding those to a new vaccine formula, both Lalvani and Sette suggest, could widen the protection of vaccines against variants.;;;
"A few companies have such 'T-cell enhanced' vaccines in the works. Gritstone and ImmunityBio, biotech firms in California ... have started clinical trials. Including more of these proteins in a shot could create a vaccine capable of boosting your immunity against whatever variant comes along."
Read study: https://www.nature.com/articles/s41467-021-27674-x
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