It’s not just temperatures that continue to rise in the Northern Hemisphere. It’s the summer of infections again. The chance of getting Covid is higher than ever due to ultra-transmissible and immune-evading sub-variants. But wastewater analyzes — perhaps the best indicator for communities — are an optimistic note.
T cellsPhoto: Flickr
In the U.S., nearly half of laboratories testing water from sewage systems reported covid levels between 60-100% of their all-time highs, according to the Centers for Disease Control, now famously the CDC.
However, “long Covid” should not be forgotten: studies show that repeated infections – even asymptomatic or mild – increase the risk of long-term suffering or death.
But let’s continue on an optimistic note: Covid variants can bypass antibody dams as much as they want, but they still have to fight T cells, the other (often neglected and poorly understood) half of our immune system.
Antibodies are specialized proteins produced by the immune system. They look for pathogens to inactivate or destroy, but they don’t last long – usually a few months. They attach to specific components of the virus, mutate with new variants, and thus reduce their effectiveness.
T cells, a type of white blood cell produced by stem cells in the bone marrow, do not prevent infection or long-term covid disease. But they are capable of greatly reducing the severity of infection with Covid, a deadly virus that can be silenced even by a few people’s T-cell response.
Rethinking herd immunity
Because the T cell response is not limited to certain parts of the virus, such as antibodies, they continue to attack even after the virus mutates or changes shape. And the protection they provide lasts for a long time, even years in some cases. Larger numbers of T cells in the population — after vaccinations or re/infections — could lead to less severe reactions to the spread of new variants, experts say.
“T cells are a type of gain that I underestimate,” says Dr. Duane Wessman, a professor at Harvard Medical School and principal investigator in the Division of Rheumatology, Immunology, and Allergy. We have The community is a bit depressed as everyone is affected by the new species. But T cells are active all the time and do a good job of protecting us from severe forms of the disease.”
According to a study published this spring in the journal Nature Immunology, Covid infections produce a “robust” T-cell response that lasts at least 15 months. A 2020 study published in “Nature” found evidence of a T-cell response 17 years earlier in patients infected with another coronavirus — SARS, which caused a pandemic in 2002 with hundreds of dead victims.
Classic herd immunity — a possible conclusion floated by some officials at the start of the Covid pandemic — is unlikely because the virus continues to mutate, vaccines aren’t always available where they should be and antibody defenses wane. T cells are less potent but provide durable protection against severe disease on a population scale—a kind of “herd defense,” although the help they provide depends on the individual response of each organism.
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