“Even if you’ve gotten a vaccine there is still a chance,” albeit a “much lower” one, “that you can get symptomatic infection” after contracting the virus from an unvaccinated person, Offit explained. “There is still a chance that you can get serious infection and there is still a chance you can be hospitalized or die from that infection.”
In particular, immunocompromised people, who already have moderately to severely weakened immune systems, “are especially vulnerable to COVID-19, and may not build the same level of immunity” from the vaccines compared with people who are not immunocompromised, the CDC says. That’s why the Food and Drug Administration authorized a third dose of the mRNA vaccines for certain immunocompromised people.
Dr. Mounzer Agha, a hematologist and director of the Mario Lemieux Center for Blood Cancers at the University of Pittsburgh Medical Center who has studied blood cancers and the vaccines, told the Washington Post in May that in order for cancer patients who don’t develop immunity from the vaccines to be protected, they need people around them to be vaccinated. “Everyone knows someone who has cancer. And if you care about that person, you should get the vaccine and tell your friends to get it,” Agha told the Post.
Also, studies show vaccine effectiveness against infection and milder forms of illness wanes over time, and the elderly can experience immunosenescence, a decreased immune response due to aging. On Sept. 17, the FDA’s Vaccines and Related Biological Products Advisory Committee unanimously recommended an emergency use authorization for a booster dose of the Pfizer/BioNTech vaccine for those age 65 and older and those at “high risk of severe COVID-19,” to be given at least six months after completion of the primary two-dose series.
The CDC tracks reports of hospitalizations and deaths that occur after “breakthrough infection,” which is the term it uses when a person contracts the coronavirus that causes COVID-19 at least two weeks after receiving all recommended doses of one of the approved or authorized vaccines. The agency used to report all known instances of breakthrough cases, including the asymptomatic and mild infections, but changed its reporting system in May to focus on “severe cases of vaccine breakthrough.”
As of Sept. 13, the CDC had received reports of 15,790 patients with a COVID-19 vaccine breakthrough infection who were hospitalized or died. That was out of more than 178 million people in the United States who had been fully vaccinated against COVID-19.
About one-fifth of the deaths (516 of 3,040) and hospitalizations (2,562 of 12,750) were “asymptomatic or not COVID-related,” the CDC said.
The Children’s Hospital of Philadelphia actually answered Carlson’s question years ago, in a pre-COVID-19 featured article titled “If Vaccines Work, Why Do Unvaccinated People Pose a Risk?”
In addition to the point about all vaccines being less than 100% effective, the September 2017 CHOP post noted that more unvaccinated people in a population leads to more virus transmission.
“The greater the number of unvaccinated people in a community, the more opportunity germs have to spread. This means outbreaks are more difficult to stem and everyone is at greater risk of exposure — including vaccinated people,” it said.
Johns Hopkins University epidemiologist David Dowdy made a similar point.
“Unfortunately, while the vaccines are highly effective — and particularly effective against serious disease — they are not perfect,” he told us in an email. “Whenever transmission rates go up, therefore, the risk goes up for everyone.”
Based on the number of COVID-19 cases, Dowdy calculated that when compared with mid-June, the risk of developing COVID-19 in the U.S. — regardless of vaccination status — had increased 15-fold as of mid-September, when the CDC said there was high community transmission in every state.
“In other words, there is a higher risk of a vaccinated person getting COVID-19 in September than of an unvaccinated person getting COVID-19 back in June — just because everyone’s risk has gone up,” Dowdy said.
Still, the risk is higher for the unvaccinated. A CDC study published Sept. 10 — but based on data from April to mid-July — found that, due to the delta variant, the unvaccinated (including those who were only partially vaccinated) were nearly five times more likely to become infected, about 10 times more likely to require hospitalization and almost 11 times more likely to die from COVID-19 than fully vaccinated individuals.
And in several states, there are so many COVID-19-related hospitalizations — the vast majority of which are unvaccinated patients — that beds in intensive care units are near capacity, making it difficult not only to treat COVID-19 patients but those with medical emergencies not related to the disease.
It’s also possible that an unvaccinated individual could transmit the virus to a vaccinated parent who could pass it on to a child or children under the age of 12, who currently are not eligible to be vaccinated. On Sept. 20, Pfizer and BioNTech announced clinical trial results showing that its vaccine was safe and effective for children ages 5 to 11 — but the vaccine still needs to be authorized or approved for that age group by the FDA.
In a Sept. 15 Washington Post opinion piece, Dr. Leana Wen, an emergency physician and visiting public health professor at George Washington University, and Sam Wang, a professor of neuroscience at Princeton University, compared being unvaccinated in public to drunken driving.
“Some who argue that vaccination is solely a matter of individual choice would say that you can choose to protect yourself. If you’re vaccinated, why do you care if others around you aren’t?” the professors wrote. “But again, consider the analogy: Three out of every eight people killed are not the intoxicated driver, but their passengers or people in other vehicles. Similarly, with covid-19, the risk is borne not only by the person making the decision but also by others who cross their path.”
“The vaccine is simultaneously like a great seat belt and a choice to drive sober,” they added. “The seat belt reduces your chance of severe injury in an accident. Driving sober reduces the risk of the accident in the first place. The vaccine does both, but it still matters if you’re surrounded by reckless drivers. No vaccine is 100 percent effective, and the more virus is around us — in this case, carried by the unvaccinated, who are five times more likely to be infected and thus to spread coronavirus — the more likely the vaccinated are to become infected.”
Not everyone will agree with that comparison, but it is nevertheless an illustration of the risk that exists.
Editor’s note: SciCheck’s COVID-19/Vaccination Project is made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over FactCheck.org’s editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation. The goal of the project is to increase exposure to accurate information about COVID-19 and vaccines, while decreasing the impact of misinformation.
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Dr. David Dowdy, Johns Hopkins University associate professor of epidemiology. Email sent to FactCheck.org. 15 Sep 2021.
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