Misleading: It is misleading to claim that vaccines are useless because vaccinated people can still become infected with the virus that causes COVID-19. The COVID-19 vaccines that are authorized for emergency use significantly reduce the number of people who fall ill from the disease, subsequently reducing the burden placed on healthcare systems. The benefits of COVID-19 vaccination outweighs the risks associated with severe COVID-19 infections.
Misleading: The recommendation that vaccinated people still wear masks to reduce the spread of COVID-19 does not mean that the vaccines are ineffective. Data suggest that COVID-19 vaccines reduce transmission to some degree, although studies are ongoing to determine by how much. Therefore, health authorities currently recommend a combination of vaccination and mask-wearing to reduce transmission and the number of COVID-19 cases.
FULL CLAIM: There is no reason to get COVID-19 vaccines because vaccinated people can still get sick and are still required to wear masks
To date, more than two million people have died from COVID-19 worldwide. Several vaccines against COVID-19 received emergency use authorization and countries have started their vaccination campaigns. Around the same time, claims that COVID-19 vaccines don’t protect vaccinated individuals from the disease nor from virus transmission started spreading on social media. One example is this cartoon questioning the usefulness of COVID-19 vaccination by stating that vaccinated people aren’t immune and are still required to wear masks.
These claims are misleading because they overlook the benefits from COVID-19 vaccines as demonstrated in publicly available clinical trials. The claims are based on the erroneous belief that vaccines should be 100% effective to work, also known as the Nirvana fallacy, and, by doing so, propagate the false notion that COVID-19 vaccines are useless.
COVID-19 vaccines significantly decrease the risks of developing the disease among vaccinated individuals
The claim that vaccinated individuals can still get COVID-19 is misleading because it fails to report the scientific evidence regarding vaccine efficacy.
As of February 2021, three COVID-19 vaccines have been authorized for emergency use in the U.S and/or the European Union: the mRNA-based vaccines from Pfizer-BioNTech and Moderna, and the adenovirus-based vaccine from the University of Oxford and AstraZeneca. The vaccines were tested in large clinical trials prior to their authorization, which showed that the vaccinated groups had significantly fewer symptomatic COVID-19 cases compared to the unvaccinated groups.
Specifically, in one clinical trial, 18,198 volunteers received the Pfizer-BioNTech vaccine and 18,325 volunteers received the placebo control. The trial monitored the occurrence of COVID-19 cases as defined by a positive COVID-19 PCR test and the presence of one symptom of the disease, such as cough, shortness of breath, fever, and loss of smell. The researchers observed 95% fewer confirmed cases of COVID-19 among the vaccinated group compared to the group that received the placebo.
The clinical trial for the Moderna COVID-19 vaccine produced similar results, where the vaccinated group had 94.5% fewer symptomatic COVID-19 cases compared to the unvaccinated group.
A pooled analysis of clinical trials conducted in the U.K. and Brazil found that the Oxford-AstraZeneca vaccine reduced the number of symptomatic COVID-19 cases by 62%.
These vaccines not only significantly reduced the number of people exhibiting COVID-19 symptoms, but they also drastically reduced the number of people suffering from severe forms of the disease. The Pfizer-BioNTech vaccine showed a 66% efficacy at reducing the number of severe COVID-19 cases compared to the unvaccinated group.
In the Moderna clinical trial, thirty patients developed severe cases of COVID-19, including nine hospitalizations: none of them received the vaccine. In the Oxford-Astrazeneca vaccine trial, 10 people developed a severe form of COVID-19 who were all in the unvaccinated group.
In several countries, COVID-19 vaccine roll-out began in early December 2020. While it is still early in the vaccination process, vaccination is significantly curbing the spread of COVID-19 in some regions around the world. For example, as of 8 February 2021, Israel vaccinated 40% of its population, including 90% of the population above 60 years old. The Israeli Ministry of Health reported a 41% drop in new COVID-19 cases among individuals older than 60 after the first dose of vaccine. As this Nature news article explains, the available data suggests that the reduction in COVID-19 cases is due to the vaccines and not other preventative measures, such as physical distancing.
Overall, data from clinical trials as well as vaccination campaigns in numerous countries indicate that the three COVID-19 vaccines authorized for use effectively reduce the number of people who get sick from COVID-19, including severe forms of the disease.
As with other safety measures, COVID-19 vaccines do not remove all possible risks. For example, even though seatbelts don’t prevent all deaths from road traffic accidents, they still reduce the risk of death by a considerable degree. Although some individuals who receive COVID-19 vaccines can still develop the disease, the vaccines significantly reduce the risk of developing symptomatic and severe cases. The claims are therefore misleading by insisting that a vaccine must be 100% effective before it can be considered useful.
COVID-19 vaccines may reduce disease transmission, but conclusive results aren’t available yet
Some claims suggest that individuals who received COVID-19 vaccines should no longer need to wear face masks and or follow physical distancing recommendations. This assumption is incorrect. Public health authorities still recommend that people wear masks after they are vaccinated to reduce the spread of COVID-19.
Another claim made in social media posts and memes questions the usefulness of vaccines since people must still wear masks even after they are vaccinated. This claim is misleading as it ignores how vaccinated individuals develop immunity and how vaccines and mask-wearing differ in their effects on the COVID-19 pandemic.
First, it takes several weeks for a person to develop immunity to COVID-19 after they are vaccinated, meaning that someone is still susceptible to the disease immediately after vaccination. As of February 2021, the authorized COVID-19 vaccines require two doses, usually spaced three or four weeks apart. It then takes approximately two weeks after the final dose to provide the vaccinated individual maximum protection against the disease. Therefore, it is important for vaccinated people to continue following recommendations to reduce the spread of COVID-19, including wearing face masks and physical distancing.
Second, vaccines are mainly intended to protect a person from developing a disease, whereas wearing face masks are intended to reduce transmission of the disease. Even if COVID-19 vaccines underperformed in terms of limiting virus transmission, they would still remain a necessary tool for ending the pandemic given their primary goal.
The vaccine clinical trials assessed whether participants developed symptomatic COVID-19, but didn’t assess the risks of infection or transmission. This research is currently underway, but it is currently unclear whether COVID-19 vaccines can reduce disease transmission, and if so, to what extent.
Although conclusive results are not available yet, preliminary findings suggest that COVID-19 vaccines can also reduce transmission of the virus that causes the disease. For example, researchers found that a single dose of the Oxford-Astrazeneca vaccine reduced the number of individuals with a positive COVID-19 PCR test by 67%. This indicates that fewer people were virus carriers two weeks after they received the vaccine compared to the control group, suggesting that vaccinated people are less likely to transmit the virus.
Data on disease transmission are not yet available for the Pfizer-BioNTech and Moderna COVID-19 vaccines because regular PCR tests were not performed during the initial clinical trials. However, data from Israel indicates that the Pfizer-BioNTech COVID-19 vaccine may also reduce transmission. In a study that has not yet been peer-reviewed, researchers looked at the viral loads of people in the weeks after they received their first doses of the COVID-19 vaccine. They found that even though some vaccinated individuals still got infected, their viral loads were lower than those of unvaccinated people. Furthermore, researchers only observed a reduction in viral load 12 days after individuals were vaccinated, which is consistent with the amount of time it takes for the vaccine to induce protection.
Overall, while some preliminary data suggests that COVID-19 vaccines can also reduce the risk of disease transmission, studies are still underway and conclusive results aren’t available yet. In many countries, only a small portion of the population is vaccinated because of limited supplies as well as manufacturing and logistical challenges. Since most people aren’t vaccinated and it is unclear how effective vaccines are at reducing disease transmission, it is important for all individuals to wear masks to reduce the spread of COVID-19.
The overall objective of the public health response to the COVID-19 pandemic is to reduce the transmission of the virus to the point that it becomes manageable by the healthcare system, or ideally, eliminate the disease from the human population. A vaccine is not a silver bullet, but rather one of the most efficient risk reduction tools available for tackling a pandemic. COVID-19 vaccines reduce the likelihood that vaccinated individuals develop severe cases of the disease, even if some can still get infected and display symptoms. In addition, the significant decrease in the number of symptomatic COVID-19 cases caused by the vaccines will ease the burden on healthcare systems. Finally, if COVID-19 vaccines have a small or significant effect on reducing transmission of the virus, they will help slow down the circulation of the virus until enough people get vaccinated to achieve herd immunity.
In summary, claims questioning the value of COVID-19 vaccines because some vaccinated people can still get infected or should still wear masks are misleading. Evidence from clinical trials and broader vaccinated populations show that the COVID-19 vaccines provide individuals with immunity to the disease. The data unequivocally show that the vaccines reduce the number of symptomatic COVID-19 cases, and preliminary reports suggest that the vaccines can also reduce the risk of transmission to some degree.
- 1 – Voysey et al. (2020) Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. The Lancet.
- 2 – Hunter & Brainard (2020) Estimating the effectiveness of the Pfizer COVID-19 BNT162b2 vaccine after a single dose. A reanalysis of a study of ‘real-world’ vaccination outcomes from Israel. medRxiv (preprint).
- 3 – Voysey & Costa clemens (2020) Single Dose Administration, And The Influence Of The Timing Of The Booster Dose On Immunogenicity and Efficacy Of ChAdOx1 nCoV-19 (AZD1222) Vaccine. SSRN (preprint).
- 4 – Levine-Tiefenbrun et al. (2020) Decreased SARS-CoV-2 viral load following vaccination. medRxiv (preprint).