Seth Wenig/AP Photo
Passengers disembarking from international flights take anonymous COVID tests for study purposes at Newark Liberty International Airport in Newark, New Jersey, January 4, 2023.
Across most of the world, COVID-19 is no longer a major emergency. In the United States and Europe, most have long since ditched masks and social-distancing measures. Bars and restaurants are operating normally. (It’s a different story in China, where practically the entire country was infected in just a couple of months, and thanks mostly to poor vaccination coverage of the elderly, possibly over a million people have died.)
Yet there is a school of thought holding that this is a terrible mistake. Various writers and activists point to supposed evidence that COVID damages the immune system, and urge a return to the strict controls and rigorous social-distancing measures of early 2020. Some have even argued that the SARS-CoV-2 virus is akin to an airborne form of HIV.
But this is simply not true. There is no solid evidence that an ordinary case of COVID damages the immune system, and a great deal of evidence that it does not.
Now, some sufferers of “long COVID” may have lingering immunity issues, particularly people who had severe cases. Something like 6 percent of Americans currently report having the syndrome, while 15 percent have had it at some point. There is every reason to continue funding and performing research on long COVID to nail down its exact causes and develop treatments.
However, research shows that in the vast majority of cases, the immune system mounts a successful defense against COVID as it does for other respiratory infections. The immune system then learns from that experience, so future infections carry a far smaller risk of serious illness. And on the level of biology, the virology of SARS-CoV-2 (the virus that causes COVID) does not equip it to infect immune system cells like HIV does.
Most importantly, as time has passed, the rate of hospitalization and death from COVID has plummeted—the exact opposite of what we would expect if mass (and in many cases repeated) infection had caused accumulating immune system damage. That can only be explained by widespread vaccination and infection causing a large net buildup of population immunity across the world.
SARS-CoV-2 might just be the most-studied virus in history at this point, in part because scientists have been able to use innovative new technology and methods only developed recently. “We understand how the major arms of the immune system behave after mild infections, all the way to severe complications, across age groups and demographics,” Andrew Croxford, a professional immunologist working in drug development, told the Prospect. “This new knowledge has been documented in granularity not seen before, largely due to significant technological advances over the last ten years.”
In the vast majority of COVID infections, “they do have an immune response—that is, getting activation, expansion of T cells and B cells, production of antibodies, and then everything is going back to normal,” Antonio Bertoletti, professor of emerging infectious diseases at Duke-NUS Medical School, told the Prospect. Croxford agreed: “The shape of an average response to this coronavirus is not all that surprising,” he said. “Innate effector cells reduce early viral spread, we generate neutralizing antibodies and cells capable of rooting out and killing infected cells, finally establishing memory cells capable of responding rapidly upon a second encounter.”
In the vast majority of cases, the immune system mounts a successful defense against COVID as it does for other respiratory infections.
Severe cases are a different story, of course. It is known that severe COVID involves immune system disruptions (though this is hardly surprising and occurs with other viruses). Some studies suggest that long COVID may be caused in part by lingering immune system dysfunction, perhaps through some ongoing presence of the virus, or chronic inflammation.
But the research is still unsettled, thanks to a huge variety of symptoms, lack of agreement on what even constitutes long COVID, and inconsistent study results. No “firm agreement on root cause or pathogenesis of long COVID has materialized. Long COVID research is hampered by reproducibility of observed perturbations in the immune system across cohorts and there is no clear immune signature found in all long COVID patients,” Croxford said.
Until more research is done, provisional conclusions are the best that we’ve got. We know that lingering post-infection side effects can happen after other ordinary viral infections like chicken pox, dengue fever, and influenza, and it appears that long COVID is more common after severe cases. A recent study found that vaccination provides some protection from long COVID, which would fit with a recent CDC survey finding the percentage of people who’ve had the disease and report long COVID symptoms falling from 19 percent last June to 11 percent in January.
But even accounting for long COVID, the idea that SARS-CoV-2 is somehow akin to HIV is simply nonsense. “Whilst SARS-CoV-2 and HIV are both RNA viruses, only HIV is a retrovirus capable of integrating into host DNA. SARS-CoV-2 does not have the necessary enzymes to integrate,” Croxford said. What’s more, “HIV and SARS-CoV-2 have non-overlapping tropism—in other words, they infect different cell types.” Specifically, while HIV typically attacks white blood cells through the CCR5 or CXCR4 proteins present on their surfaces, SARS-CoV-2 attacks cells in organ tissue through the ACE2 enzyme (using its famous spike protein).
There are a couple of papers that alleged T cell infection from SARS-CoV-2, but they are highly implausible from a theoretical standpoint and some ended up retracted. Those “papers are honestly ridiculous, that’s what they are,” said Bertoletti. Moreover, if the virus could infect white blood cells, it should be easy to replicate in the laboratory, but nobody has been able to do it. The idea “has not been convincing for something so straightforward to demonstrate experimentally,” said Croxford.
IN FALL 2022, AMERICA GOT HIT simultaneously with an early season of influenza and RSV. This prompted many to warn of a looming “tripledemic” that would perhaps be just as bad as what happened in March 2020, thanks to accumulated immune system damage from so many COVID infections.
But it didn’t happen. The RSV wave was relatively severe and early, and especially hit kids who had not been infected before. Many children’s hospitals were seriously burdened. But then cases fell rapidly not long afterward. The flu season, meanwhile, started early but has not been appreciably worse than the one of 2019-2020, and quite a bit less bad than that of 2017-2018 (though there could be another wave in the spring, to be fair). Most tellingly of all, despite its moderate severity this flu season has been considerably worse in terms of hospitalizations than COVID has been—as compared to the previous season, when COVID was exponentially worse.
This set of facts is simply impossible to square with the hypothesis that COVID damages the immune system. In reality, the root explanation is differing levels of population immunity. There was very little transmission of flu or RSV in 2020 and 2021, and so there were effectively two seasons of both rolled into one when normal life resumed in 2022. Very young kids especially who had never been exposed to either virus had an especially rough time of it. By contrast, almost everyone has been exposed to COVID by now (through infection or vaccination), and so the winter was mild compared to the last two years.
That said, it’s important to note that this does not imply that it was a bad thing to do social distancing and such to fight the pandemic in its initial stages, just that it would necessarily have a modest side effect when normal life did resume.
At any rate, as I have previously argued, all evidence suggests that COVID is going to be with us for the foreseeable future, just like influenza and other coronaviruses. It is hyper-contagious, it is widely circulating in every single country on the planet, and it is established in numerous reservoir species. Virtually every single person is going to be exposed sooner or later—indeed, probably the vast majority of the world population has already been infected at least once. Dr. Bertoletti, for instance, recently finished a study of a remote village in Kenya. “We targeted 100 subjects that were living in a very rural area, no symptoms, nothing, never been in contact with anyone who got COVID,” he said. “Forty percent of them had antibodies, and 90 percent of them got T cell multi-specifics showing they were in contact with the virus.” What’s more, this was done before the massive omicron wave.
Luckily, we’ve got vaccines that reduce the risk of infection, drastically reduce the risk of severe illness and death, and probably reduce the likelihood of long COVID. It follows that the best step both nations and individuals can take to protect themselves is to get vaccinated with the most up-to-date-shots—against COVID and the flu (as well as RSV when that vaccine is released). “Vaccination will continue to form the most important part of our population immunity and prevention of bad COVID outcomes. All signs point to another annual vaccination for those wanting to protect themselves, or those at higher risk,” said Croxford.
Masking, testing, air quality improvements, and other non-pharmaceutical interventions have their place—particularly in vulnerable locations like hospitals, schools, homes with newborn infants, and so on—but they cannot possibly halt transmission entirely. Not even the full weight of the Chinese police state could manage that after omicron hit.
Because there is another side to the equation here. The suggestion from some quarters that normal social life should be more or less permanently suspended carries its own risks. Studies have found social isolation or loneliness to be associated with depression, anxiety, memory loss, dementia, and death, particularly among the elderly. Humans, like all primates, are not meant to live like solitary scavengers. (This is why solitary confinement is torture.) For the vast majority of people, there is every reason to return to normal life. Just get your shots, and mask up or stay home if you aren’t feeling well.
