Were we lied to about the Covid vaccines?

Remember the remarkable first reports of Covid vaccine efficacy in the fall of 2020? There was talk during their development about how good the vaccines would have to be to achieve so-called "herd immunity." Seventy percent? Eighty? More?

So when the trials showed the two new mRNA vaccines had around 95 percent efficacy against infection, it was the kind of stunningly good news that nobody dared hope for.

A wild rush to vaccinate ensued in early 2021. The Biden administration far exceeded its own aggressive goals to get many millions of doses in arms. By March 12, 100 million doses had been administered in the United States. By the end of March, 130 million. Back then almost everybody wanted to be vaccinated, and local, state, and federal government agencies all aligned energetically to accomplish the mission. It was a remarkable achievement.

But in early summer 2021, the bloom seemingly began to come off the rose. The first "breakthrough" infections were reported. Thousands of fully vaccinated (with two doses) men gathered in Provincetown, Massachusetts, for a July 4 celebration. 346 of them developed Covid, many with mild or no symptoms. Four were hospitalized. It suddenly seemed in the public's mind that the vaccines were failing; that the promised protection had been a sham.

Many believed they'd been lied to; that they'd been falsely promised long term immunity; that getting vaccinated would put Covid in the rear-view mirror more or less permanently.

All this was the result of a complicated mix of understandable initial enthusiasm, less than ideal communication (also understandable) about what to expect going forward, and a growing understanding of the virus and the vaccines over time. Don't forget: In the early going we didn't know much about how the virus would behave, only that it was killing thousands of people. In the messy context of an evolving pandemic, this confusion was unsurprising and, in my opinion, quite forgivable. Inevitable, even. The correct early urgency was getting people vaccinated; doing so saved countless lives. What would come next wasn't nearly as important.

Even so, what was not well communicated was that the early strong protection against infection was never likely persist, and not just because the virus was evolving more ways to evade the immune system. (A succession of variants became ever more virulent, even as they became somewhat less deadly.) In his book Tell Me When It's Over, Dr. Paul Offit M.D., a vaccine specialist, beautifully explains why that is so, and in so doing answers questions I've long had about why some vaccines provide lifelong immunity against certain diseases, while other's don't.

Consider the measles vaccine. If you have had measles, or have had two doses of the measles vaccine, you will likely be immune to infection for the rest of your life. The reason has to do with how the immune system works, and with the very long incubation time of the measles virus, which is 10 to 14 days. I'll get back to that below.

The immune system consists of several components. The front-line immune response involves antibodies, which directly deactivate the virus. If you have abundant antibodies circulating against the virus, then you're protected against outright infection, because the antibodies immediately go to work against the virus as soon as it's detected. Both vaccination and natural infection stimulate the body to produce antibodies, but the antibodies are short lived. They typically fade after 3 to 6 months, after which you're not well protected against infection. 

So the initial 95 percent efficacy against infection of the Covid vaccines was quite real. Because the vaccine trials only lasted a few months, most vaccinated participants had abundant antibodies over the duration of the trials, and were thus protected against infection. The urgency to get the vaccines to the public meant the trials were necessarily short, and so they were unable to test the longer term durability of the induced antibodies. Not that it really mattered, at least for purposes of keeping people alive.

The other important components of the immune system are memory B cells and memory T cells. The T cells kill the body's own cells that have become infected. The B cells recognize the virus and stimulate the immune system to produce antibodies which, as we've seen, deactivate the virus directly and can actually protect against infection if they're present when the virus shows up. The problem is that it takes time for the B cells to ramp up the immune response to produce abundant antibodies. The SARS-CoV-2 virus, which causes Covid, has a very short incubation period. It takes just 3 days from initial exposure to the onset of symptoms. That's not enough time for the B cells to make enough antibodies to stop the infection. If antibodies weren't already present, then at least a mild infection is inevitable. That's not a deficiency in the vaccine; it's entirely a function of the virus's short incubation period.

Whereas a mild infection develops just a few days after initial exposure, it takes a couple of weeks for a serious Covid infection (one that requires hospitalization) to develop. That's ample time for the B cells to ramp up antibody production. Eventually antibodies become sufficiently abundant to shut down the disease progression, and serious disease doesn't develop. That's crucial. But even if you're spared from serious disease, you can still have an infection that's plenty unpleasant.

And whereas antibodies against SARS-CoV-2 fade after 3 to 6 months, the memory B cells and T cells are longer lived—perhaps much longer. We're still trying to determine exactly how long, but current evidence suggests one year to perhaps many years. The upshot is that the vaccines produce short lived (antibody) protection against infection, but long term (B and T cell) protection against severe disease. Thus the protection provided is real and significant. It's just that we always wanted to not get infected at all, and that is clearly not what we got.

But what explains the lifelong immunity against measles infection, and why don't the Covid vaccines provide something similar? It is this. Absent recent exposure to the virus, you don't have circulating measles antibodies, just like you might not have circulating SARS-CoV-2 antibodies. But if you've ever had measles or have been vaccinated against it, you do have memory B cells and memory T cells that normally last a lifetime. The long measles incubation period of 10 to 14 days gives the B cells time to manufacture antibodies when you're exposed to the virus, and those antibodies shut down the infection before any symptoms occur. Unlike with Covid, you don't just have protection against severe disease, but against mild disease too. This explains what's sometimes called "sterilizing immunity" against measles, plus other viruses such as polio. It's all about how long the particular virus's incubation period is.

Because coronaviruses have very short incubation periods, we probably shouldn't expect vaccines to ever provide durable protection against infection. But they do provide very good protection against hospitalization, ventilation, and death. By the way, because of its short incubation period, the notion of "herd immunity" against Covid, when understood to be no disease spread in the community, is nonsense. The virus will always spread because infection occurs before the immune system can stop it. (We knew from very early in the pandemic, in 2020, that people could spread Covid before they developed symptoms.)

Should those caveats have all been thoroughly aired at the outset, in late 2020, as vaccines were about to be deployed? I don't know. The overall communication was unsurprisingly muddled, given the novelty of the virus and the urgency of the moment, with many thousands of deaths. Stopping those deaths involves protecting against severe disease, which the vaccines always did and still do. But the reported 95 percent efficacy against infection was absorbed by the public as an exhilarating guarantee, even if it wasn't meant to be.

It's worth noting that Anthony Fauci himself worried as early as June 2020, months before the vaccines became available, that vaccine immunity against Covid might not be durable. If Covid-19 acts like other coronaviruses, he said, "it likely isn't going to be a long duration of immunity. When you look at the history of coronaviruses, the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that's protective ranges from three to six months to almost always less than a year. That's not a lot of durability and protection."

Fauci said that. 

The record shows over and over that claims that Fauci over-promised about the vaccines are just false. In a February 4, 2021 interview, just as the vaccination campaign was ramping up, Fauci said: "One of the things that we do know is that the vaccines that we have, although they are less effective in preventing disease ... when you look at serious disease with hospitalizations and deaths, the vaccines still have a pretty important, positive effect even on the mutants [ie., the newly emerging variants -mb]."

Less effective at preventing disease, Fauci said. So even as the vaccines were being rolled out, Fauci was noting that vaccines don't prevent infection, but they were still important.

On February 27 Fauci said vaccinated people "could conceivably get infected, get no symptoms and still have virus in your nasal pharynx, which means that you would have to wear a mask to prevent you from infecting someone else, as well as the other side of the coin, where you may not be totally protected yourself."

Not totally protected yourself. 

To underscore everything we've said here: Covid vaccines generally don't prevent infection, at least not after the antibodies fade. But they do—emphatically do—protect against severe disease. And that might well keep you from dying. There are various analyses out there, but the consensus opinion is that vaccines prevented a few million deaths in the U.S., and around 15 million worldwide. It's estimated that a couple of hundred thousand people in the U.S. died unnecessarily because they refused to get vaccinated. And even now, after a progression of variants—Alpha, Delta, Omicron, etc.—the vaccines are still preventing severe disease.

If you were under the misunderstanding that the vaccines would prevent infection forever, get over it. What to do going forward? Writing in 2023, Dr. Offit said that three vaccine doses (the primary series plus a booster), or natural infection plus two vaccine doses, have both been shown to produce durable immunity against severe disease. Offit says it's incumbent upon the CDC to ultimately determine how long that immunity (provided by the memory B and memory T cells) lasts. (Good luck with that under RFK Jr.) Offit assumes for now that the protection is relatively durable, especially for younger people or those without other medical conditions. Most of the deaths now occurring are in people over age 75; for them it's a very different story.

Offit wrote: "I'm under 75 and otherwise healthy. I have received three doses of a Covid vaccine; the last dose was given in November 2021. Six months later I had a mild Covid illness caused by one of the Omicron variants (probably BA.2). I will likely be protected against severe Covid for years. But I don't know that. And I need to know. I will look to the CDC and academic researchers to determine how long immunity against severe disease lasts for people like me and then, only then, will I get a booster dose."

Me? I'm over 65 but under 75. To date I've mostly been boosted every six months or so. I have never had a confirmed Covid infection. In the past year I had a viral infection that tested negative for Covid. I also had a weeks-long viral infection in early 2021, starting about 5 days after my second vaccine dose in the primary series. At-home testing was not available back then. Covid? No way to know.

By now an overwhelming majority of the country has some Covid immunity, either from infection or vaccination or both. The nationwide death rate has dropped accordingly. Presently persons over 75 are by far at the highest risk of severe disease and death. Regular boosting makes sense for them. Dr. Offit, a pediatrician, also says women should also get a Covid shot during each pregnancy. That's because pregnant persons have serious illness at significantly higher rates than non-pregnant persons. Furthermore, late in pregnancy a fetus obtains antibodies against Covid through the placenta, and those antibodies provide protection for the first half year of life, until the baby is old enough to be vaccinated. Perversely, HHS Secretary Robert F. Kennedy Jr. has personally revoked the CDC's previous recommendation that pregnant women get vaccinated.

Finally, Kennedy recently canceled $500 million in government-funded mRNA vaccine research, terminating 22 grants. These involved research on mRNA vaccines against influenza, against cancer, and more. Kennedy, a longtime virulent anti-vaxxer, falsely said that "these vaccines fail to protect effectively against upper respiratory infections like COVID and flu." In fact, the performance of mRNA vaccines during the Covid pandemic (and still) has been exemplary. As I've already noted, they've saved millions of lives. The mRNA platform uniquely enables very rapid vaccine development—something that will be badly needed when the next pandemic, such as bird flu, emerges. The outrage and dismay in the public health community at Kennedy's action has been profound.

Copyright (C) 2025 James Michael Brennan, All Rights Reserved

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