Vaccines are highly effective against COVID-19, but unvaccinated people can still endanger vaccinated people, contrary to Tucker Carlson’s claim on Fox News

“If you are vaccinated against COVID-19, you face no conceivable danger whatsoever from people who have not been vaccinated”; many unvaccinated people “have natural immunity and are less likely to get sick than a vaccinated person from COVID”
Incorrect: The COVID-19 vaccines are highly effective against disease, but no vaccine is 100% effective, therefore vaccinated people can still develop COVID-19. As unvaccinated people are more likely to become infected, they still expose vaccinated people to the risk of infection.
Flawed Reasoning: Carlson claimed that vaccinated people are entirely protected from COVID-19 and later stated that there are thousands of vaccinated people who died of COVID-19, which is contradictory.
Overstates scientific confidence: Data about the relative strength of COVID-19 immunity acquired from infection as opposed to vaccination are mixed. Immunity resulting from infection varies greatly between people, whereas vaccination offers more reliable and safer protection.
Vaccines provide more reliable protection against SARS-CoV-2 and with fewer risks attached compared to infection. But as with any other vaccine, they aren’t 100% effective, therefore vaccinated people remain at risk of infection when there is a high level of virus transmission in the community. The high level of transmission is primarily due to unvaccinated people in the community, who are more likely to be infected and therefore transmit the virus to others. They represent the majority of COVID-19 related hospitalization and deaths. At the same time, by fostering the transmission and replication of the virus, unvaccinated people increase the likelihood that new variants emerge.

FULL CLAIM: “If you are vaccinated against COVID-19, you face no conceivable danger whatsoever from people who have not been vaccinated”; many unvaccinated people “have natural immunity and are less likely to get sick than a vaccinated person from COVID”


More than half the U.S. population has been fully vaccinated against COVID-19 as of 12 October 2021. However, the pace of vaccination significantly slowed down compared to the first months of the campaign. In a press conference on 24 September 2021, Joe Biden insisted on the necessity of vaccinating the remaining 70 million people in the U.S. who hadn’t received a first vaccine dose yet. Biden stated that the COVID-19 pandemic was now a “pandemic of the unvaccinated” arguing that Intensive Care Units were overrun by unvaccinated, putting other medical interventions in jeopardy, which Health Feedback found was mostly accurate, as explained below.

Reacting to that conference, Fox News anchorman Tucker Carlson countered by claiming that unvaccinated people weren’t a public health threat and that “If you are vaccinated against COVID-19, you face no conceivable danger whatsoever from people who have not been vaccinated”. He further justified his claim by saying that many unvaccinated people didn’t need to get the vaccine, since many of them “have natural immunity and are less likely to get sick than a vaccinated person from COVID”. Health Feedback reviewed similar claims in the past and found them to be inaccurate.

Claim 1 (Incorrect)
Tucker Carlson: “If you are vaccinated against COVID-19, you face no conceivable danger whatsoever from people who have not been vaccinated”

Clinical trials involving tens of thousands of people demonstrated the safety and effectiveness of the COVID-19 vaccines. This was also followed by surveillance of post-vaccine adverse events after emergency use authorization corroborating data from clinical trials showing that the vaccines are safe and effective. Expert panels from the U.S. Food and Drug Administration established that the vaccines’ benefits outweigh the risks.

However, vaccines aren’t 100% effective, just like any other medical intervention. The clinical trials leading to the vaccines’ authorization reported vaccine efficacy against symptomatic COVID-19 ranging between 65% and 95% depending on the vaccine, according to the U.S. Centers for Diseases Control and Prevention (CDC). This means that the proportion of people developing symptomatic COVID-19 was 65% to 95% lower in vaccinated people compared unvaccinated people. For example, if we consider two groups of equal size, and if 500 people got sick in the placebo group, such a range of efficacy would mean that only 25 to 175 got sick in the fully vaccinated group.

The CDC also reported vaccine effectiveness from several real-world studies, many of which found effectiveness above 80%. In other words, the proportion of SARS-CoV-2 infections and symptomatic COVID-19 cases in the vaccinated population amounts to about 20% of that number among the unvaccinated.

While these numbers demonstrate the importance of vaccines in combating the COVID-19 pandemic, they also show that a small proportion of fully vaccinated people still get infected and develop symptoms. These are called breakthrough cases. The CDC recorded 13,406 cases of COVID-19-related hospitalization and 1,934 COVID-19-related deaths among the fully vaccinated, as of 4 October 2021.

Therefore, there still exists a risk of infection for fully vaccinated people, albeit to a lesser extent than for unvaccinated people, making Carlson’s claim inaccurate.

Furthermore, the longevity of vaccine-induced immunity remains an open question as of 13 October 2021. Scientific observations from Israel and Qatar showed reduced neutralizing antibody titers —the amount of SARS-CoV-2-blocking antibodies in the blood— accompanied by an increased infection rate in the months following vaccination. This could be partly due to the fact that most of the people vaccinated six months ago belonged to the elderly population, as they were among the first to get vaccinated. Vaccination is less effective in older people [1], so they could become more vulnerable to the disease after a few months.

At this point, it is not possible to draw definitive conclusions on the duration of vaccine immunity. As this BMJ editorial points out, many confounding factors exist. Confounding factors are variables that affect the outcome of an experiment, but that aren’t the variables being studied in the experiment. Failing to account for confounding factors can lead researchers to draw erroneous conclusions. In this case, it is plausible that people behaved in ways that increased their exposure to the virus following vaccination. Researchers would then observe a new surge of cases, which wouldn’t be due to vaccine ineffectiveness, but because people behave differently after vaccination in ways that alter the risk they are exposed to. It is thus premature to dismiss the possibility that vaccinated people may become more vulnerable over time, as Carlson seemed to do.

In addition, the assumptions underlying the claim doesn’t account for the situation of immunosuppressed people. As data gathered in this CDC Science Brief shows, vaccine effectiveness is lower in people who are receiving immunosuppressive therapies. This includes people who received an organ transplant, like bone marrow transplants, since immunosuppressive treatment is required to avoid rejection of the donor tissue or organ. Therefore, while this group of people can be fully vaccinated, the level of protection they receive is limited. At the same time, their immunocompromised state (a weakened immune system) means that they are more likely to develop worse outcomes from SARS-CoV-2 infection than the general population[2].

Another biological phenomenon exists that may jeopardize vaccine protection: as the virus acquires more mutations, variants may emerge that would be better able to evade the immune system. As Vaughn Cooper, professor of microbiology and molecular genetics and Lee Harrison, professor of epidemiology, medicine, and infectious diseases and microbiology, both at the University of Pittsburgh, explained in The Conversation, virus mutations are directly tied to its circulation among the population. This is because mutations occur during virus replication; the more infections occur, the more replication takes place, and the higher the chance of mutations occurring.

Since unvaccinated people are more prone to infection and transmission than vaccinated[3,4], having a large proportion of unvaccinated people among the population facilitates the circulation of the virus, which in turn increases the likelihood of new variants emerging, against which vaccines could be ineffective.

Carlson also seemed to contradict himself. In spite of his inaccurate claim that vaccinated people face zero risk from unvaccinated people, he went on to state that “Vaccines do appear to lower the death rate across the population from COVID, but they certainly don’t prevent death from COVID”. This statement is accurate, but directly contradicts his earlier claim.

In summary, vaccinated people are much more protected against COVID-19 than unvaccinated. However, they are not risk-free, given that vaccines aren’t 100% effective. Furthermore, certain groups, such as the elderly or people with a weakened immune system, are still particularly vulnerable in spite of vaccination. A large number of unvaccinated people among the population favors virus circulation, increasing the risk of variant emergence. According to the CDC, “The risk for SARS-CoV-2 infection in fully vaccinated people cannot be completely eliminated as long as there is continued community transmission of the virus”.

Claim 2 (Missing context):
Tucker Carlson: Many unvaccinated people “have natural immunity and are less likely to get sick than a vaccinated person from COVID”

Infection and vaccination share one thing in common: the immune system will learn from the experience and become more effective at fighting off the pathogen during another encounter. Because of that, some, like Carlson, argued that people who were infected by SARS-CoV-2 and recovered didn’t require vaccination. However, more context is needed. Scientific data are mixed about whether infections provide a stronger immunity. But other considerations, such as the risks associated with infection and the unpredictability of infection-based immunity, make vaccines a safer and more reliable option.

A preprint, which is a study that has not yet been peer reviewed, drew a lot of attention by reporting that fully vaccinated individuals who never got COVID-19 were more likely to get infected or develop symptoms than unvaccinated people who had recovered from COVID-19[5]. In contrast, a research study showed that the antibodies from people vaccinated with mRNA vaccines were more potent at neutralizing the SARS-CoV-2 Beta variant[6] than the antibodies from unvaccinated recovered patients. Along the same lines, other researchers found that the Moderna mRNA vaccines elicited a broader spectrum of antibodies against the virus compared to infection[7].

One important consideration is that SARS-CoV-2 infections come in many flavors. Some people remain asymptomatic while others become very ill. The virus variant involved as well as the viral load can differ between people. Therefore, the potency and duration of infection-acquired immunity is uncontrollable.

Grant McFadden, director of the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at Arizona State University, told USA Today: “Recovery from COVID results in very variable immunity to a second infection, and this is reflected in the wide range of anti-spike antibodies in recovered patients. On the other hand, the immunity from the vaccines (especially the messenger RNA versions) is much more uniform, both in terms of protection from COVID and in anti-spike antibody levels.”

It is also important to keep in mind the fact that immunity acquired from infection and vaccination complement one another and aren’t mutually exclusive concepts. This can be observed in people who are both vaccinated and have recovered from past SARS-CoV-2 infections, who are better protected than unvaccinated, recovered individuals. Therefore, even people who developed immunity against the virus from a previous infection still benefit from vaccination[5,8].

Lastly, a major difference between infection-induced and vaccine-induced immunity is that vaccines carry fewer risks than infection. Severe adverse events, like blood clots, may occur following vaccination in some cases but these remain very rare. For example, researchers found that the risk of severe thrombosis was much higher following SARS-CoV-2 infection than vaccination[9].

In conclusion, while infection may provide better protection than vaccination in some cases, vaccination offers a more standardized protection at a less risk. Even recovered patients benefit from vaccination.

Claim 3 (Mostly accurate): Joe Biden: COVID-19 is a “pandemic of the unvaccinated”

In his 24 September 2021 press conference, Biden claimed that a large majority of hospitalized COVID-19 patients were unvaccinated. As of 29 September 2021, the ICUs in many U.S. states were near capacity. According to a survey of 50 hospitals across 17 states, 94% of ICU COVID-19 patients were unvaccinated.

The CDC monitored the number of hospitalizations and deaths due to COVID-19 from April to July 2021, categorizing these by vaccination status. They found that 569,142 (92%) COVID-19 cases, 34,972 (92%) hospitalizations, and 6,132 (91%) COVID-19-associated deaths were reported among persons that didn’t completed the entire vaccination scheme recommended by the FDA, while 46,312 (8%) cases, 2,976 (8%) hospitalizations, and 616 (9%) deaths were reported among fully vaccinated persons. This means that COVID-19 hospitalizations are mostly due to unvaccinated patients. As with similar earlier claims, Health Feedback previously established that the majority of COVID-19 hospitalization were due to unvaccinated patients.

While we cannot say that the virus is only targeting the unvaccinated, it is still accurate that the large majority of COVID-19 patients can be found in that segment of the population.


In summary, unvaccinated people place other people at risk of illness, including fully vaccinated individuals. Unvaccinated people are more likely to be infected and therefore contribute to continued virus transmission in the community. This increases the odds of new virus variants emerging that could evade immunity and directly increases the risk of infection of vaccinated yet vulnerable people such as the elderly and immunosuppressed patients.



Published on: 19 Oct 2021 | Editor:

Health Feedback is a non-partisan, non-profit organization dedicated to science education. Our reviews are crowdsourced directly from a community of scientists with relevant expertise. We strive to explain whether and why information is or is not consistent with the science and to help readers know which news to trust.
Please get in touch if you have any comment or think there is an important claim or article that would need to be reviewed.