The message of the Centers for Disease Control's documents obtained by the Washington Post and the New York Times on Friday isn't specified in those documents themselves, but in one epidemiologist's reaction to them. "Herd immunity is not relevant as we are seeing plenty of evidence of repeat and breakthrough infections," Dr. Jeffrey Shaman, a Columbia University epidemiologist, told the Post.
If you're like me, you will probably need a moment to let that sink in. Until Friday morning, July 30, 2021, herd immunity was the goal we were all working towards. Remember when President Biden set his goal of vaccinating 70 percent of the population by July 4? What followed was an extended discussion among experts and politicians about whether that goal would amount to the country reaching "herd immunity." The hope was that COVID would turn out to be similar to chicken pox or measles or polio, diseases for which herd immunity was long ago reached with vaccines. When enough people had been vaccinated, those diseases simply went away, with only occasional outbreaks of measles in communities which lost their herd immunity, due largely to anti-vaccine movements.
Most experts believed that it would take vaccinating somewhere between 70 and 90 percent of Americans for the country to reach something resembling herd immunity. The fact that COVID is a global pandemic, with many countries in the developing world lacking widespread vaccine distribution, argued against the kind of herd immunity eventually reached against diseases like polio. Still, the goal seemed within reach if enough of us could be convinced to get vaccinated. At that point, it was hoped, normal life in this country could resume, with people eating in restaurants, going to the movies, attending concerts, singing in church choirs, playing sports and attending school uninhibited by requirements to social distance or keep wearing masks.
On Friday, that hope went out the door. The CDC internal health document obtained by the Post and the Times urges federal health officials to "acknowledge the war has changed." What changed the CDC's approach to COVID was "unpublished data from outbreak investigations and outside studies showing that vaccinated individuals infected with delta may be able to transmit the virus as easily as those who are unvaccinated," according to the Post.
Herd immunity has to do with transmissibility. A disease goes away when enough people become immune to the infectious agent such that it can no longer be transmitted among a population. The CDC on Friday essentially admitted that being vaccinated against COVID doesn't make you immune. You can still contract the disease, especially the delta variant, and having become infected, you can still transmit the disease to others whether you have symptoms or not.
If you get down in the weeds of the CDC findings, you find that the lack of immunity provided by the current vaccines has to do with the way the antibodies produced by the vaccines act within the body. When the COVID vaccines are injected, the antibodies produced by the human immune system appear mostly in the blood. "Some antibodies may make their way into the nose, the main port of entry for the virus, but not enough to block it," the Times reported Friday. "The Delta variant seems to flourish in the nose, and its abundance may explain why more people than scientists expected are experiencing break-through infections and cold-like symptoms."
Vaccinated people can spread the virus almost as easily as unvaccinated people because the so-called "viral loads" in their noses and upper respiratory tracts can be nearly as strong as in unvaccinated people. When vaccinated people become infected, the virus attempts to travel from the nose and throat into the lungs. This is where the antibodies built up by the vaccines go to work, preventing a severe enough infection to need hospitalization.
"The vaccines — they're beautiful, they work, they're amazing," Dr. Frances Lund, a viral immunologist at the University of Alabama at Birmingham, told the Times. "But they're not going to give you that local immunity." Vaccinated people will be contagious for a much shorter time, Dr. Lund told the Times. "But that doesn't mean that in those first couple of days, when they're infected, they can't transmit it to somebody else."
There's the rub about COVID. Since vaccinated people can still "catch" the delta variant of COVID and transmit it to other people almost as easily as unvaccinated people, "in some sense, vaccination is now about personal protection — protecting oneself against severe disease," Dr. Shaman, the Columbia University epidemiologist told the Post. So it's not about the "herd," it's just about you.
This is why the CDC's findings this week are a game-changer. It's also why the CDC has released new guidelines suggesting a return to mask-wearing, even among vaccinated people, in areas of the country that are experiencing an uptick in breakouts of the disease. Getting the vaccine doesn't keep you from getting the disease, and it doesn't keep you from spreading it.
Of course, this might raise the question among the unvaccinated of why they should get the vaccine at all. If everybody can still get the disease and spread it to the extent that the CDC is going back to saying we've got to wear masks again – all of us, vaccinated and unvaccinated alike – what's the use?
For one thing, all the available vaccines provide protection against coming down with a bad enough case of the disease that you'll need to be hospitalized and run the risk of dying. And vaccines at least lower the possibility that you'll contract the disease and be likely to spread it. So we've gone from expecting that the vaccines will make us immune to the knowledge that the vaccines will protect us from severe infection and the symptoms of "long COVID" and the possibility of dying from the disease.
The message is, COVID is as contagious as chicken pox, Ebola or the common cold, and getting vaccinated isn't going to prevent you from catching it. But it will save your life.
That is a more nuanced argument for the vaccines, and it will have to be the argument that health care professionals and politicians take to the population that isn't yet vaccinated. Telling them that getting vaccinated is some kind of cure-all would be a lie, so tell them the truth.
I think the other thing the CDC findings published on Friday tell us is that the unvaccinated population is no longer "the problem." They are part of the problem, because they can of course catch the disease and spread it, but, as we just learned, so can those of us who are vaccinated. We may be returning to the point where "the problem," if there is one, is more about people who refuse to adhere to mask mandates, or those politicians who, faced with outbreaks of the disease, refuse to impose them.
If there is an enemy in the war against COVID it's the virus itself, which is far more virulent than we knew. It is mutating, and mutations like the delta variant are making the disease much worse than it was in the beginning. I think we will have to assume that there will be new mutations, new variants, meaning this disease is going to be with us in one form or another for years – maybe forever, like the seasonal flu and the common cold. We're going to have to learn to live with the disease even if more and more Americans come around to getting vaccinated, because while the vaccine may protect us as individuals, it will never protect us as the "herd" we hoped to become by getting vaccinated. We're never going to reach herd immunity, but it behooves us as a nation to reach a herd understanding that for better or worse, we're all in this together.