Why do you still need to wear a mask after getting the COVID-19 vaccine?

Getting the vaccine does not mean you can ignore precautions. As the promise of a COVID-19 vaccine is fulfilled amid the rollout of the Pfizer/BioNTech and Moderna vaccines, the need to continue wearing masks, washing your hands, and maintaining social distancing remains mission-critical to protecting lives.

Public health measures have been the main tools at preventing infection and transmission of the virus. Wearing a face mask can reduce an individual’s risk of infection by 70%. The emergency-use authorization of the Pfizer/BioNTech and Moderna vaccines provides an opportunity to further decrease the risk of illness due to COVID-19. However, vaccines may give people a false sense of security that masks are no longer needed. Unfortunately, that is not the case. Vaccination teaches the body how to successfully fight the virus without actually getting sick. This is in contrast to public-health measures, which rely on decreasing public exposure to the virus. To effectively contain this pandemic, reducing exposure to the virus and supporting vaccination campaigns must continue.

Here are the reasons why you need to continue wearing a mask (and practice other recommended safety guidelines) during and after vaccination:

Vaccination does not provide instant immunity. Pfizer/BioNTech and Moderna vaccines require two doses administered weeks apart. Depending on the vaccine, it can take four to six weeks from initial dosing to achieve immunity and protection levels comparable to those in clinical trials. During this time it is still possible to contract an infection and fall ill.

Vaccination trials did not track whether participants wore masks. Given a lack of data, it is not clear whether vaccination efficacy had anything to do with vaccine trial participants adhering to public-health safety measures, such as wearing masks.

The real world does not mimic a controlled clinical trial. Factors such as how the vaccine is stored, transported, and administered, as well as the physical health of an individual, can determine real-world effectiveness of the vaccine.

The herd immunity threshold for COVID-19 is unknown. Herd immunity occurs when enough of the population is exposed to the virus, typically through vaccination, and limits the ability of the virus to spread. The percentage of the population requiring immunization to achieve herd immunity varies by disease. The herd-immunity threshold for COVID-19 has yet to be established, and the duration of vaccine immunity is unknown. The length of vaccine coverage is yet to be determined and will be monitored as vaccination campaigns are rolled out.

It is unclear whether vaccines prevent transmission of COVID-19. In their clinical trials, Pfizer/BioNTech and Moderna did not track cases of asymptomatic infections with COVID-19. This means the ability of the vaccine to decrease transmission was never evaluated.

Much of that success relies on continued cooperation. It is imperative that every eligible individual gets vaccinated. Vaccination significantly decreases the risk of getting sick, but it does not signal the end of public-health measures. As we further understand this virus and the vaccine’s efficacy, we must continue to follow public-health measures, such as wearing a mask, washing hands, and social distancing, aimed at decreasing exposure to coronavirus.