Why You Can Still Get Infected with COVID-19 After Being Vaccinated

Man washes his hands at a sink

Most of us are looking forward to being vaccinated and getting back to normal life. Unfortunately, this will not happen right away. Until herd immunity is reached, we will all still need to be careful. Here are four main reasons why you should continue taking the appropriate safety measures even if you received your vaccine.

1. Immunity Doesn’t Begin Immediately

Once you are vaccinated, it takes two weeks after your last dose for the vaccine to fully protect you. It is possible to be exposed right before or after vaccination, or in the window before your body builds up full immunity. This means that after vaccination, you could still get COVID-19 if you stop following COVID-19 prevention measures, like masking and physical distancing.

2. Vaccines Don’t Provide Complete Protection

No vaccine is 100 percent effective. However, 95% efficacy means that 5% of fully vaccinated people are still capable of getting infected with the virus that causes COVID-19. What’s more, Moderna and Pfizer/BioNTech are still studying whether the vaccine can prevent people who are vaccinated from developing asymptomatic infection and transmitting it to others. This means that even if you are vaccinated it is possible that you could still catch the virus and spread it without knowing.

Importantly, the vaccine itself cannot cause COVID-19 infections. As the CDC states, the vaccines do not contain “the live virus” which means that “a COVID-19 vaccine cannot make you sick with COVID-19.”

3. Immunity May Decline Over Time

Like the tetanus shot that most adults get once every 10 years, the effectiveness of some vaccines can decline over time. Because SARS-CoV-2 (the virus that causes COVID-19) and the vaccines against it are so new, there have not been long-term studies on the efficacy of the vaccine. It is only with time that scientists and the public will learn how long vaccine protection will last.

Even if you’ve already had COVID-19 and recovered, it’s important to get vaccinated since we do not know how long protection after COVID-19 infection (natural immunity) lasts.

There is also the possibility of SARS-CoV-2 developing a mutation. Like the influenza virus, SARS-CoV-2 may mutate and create variants with some degree of resistance to current vaccines. If that does happen, vaccine manufacturers will be able to alter their vaccines to include these new variants (similar to influenza vaccinations that change each year to include the most common anticipated viral strains). The existence of variants that may only be partially covered by currently available vaccines emphasizes the importance of maintaining physical distancing, masking and hand hygiene practices.

4. You May Still Pass COVID-19 to Others

It is possible that you could be infected with SARS-CoV-2, the virus causing COVID-19, asymptomatically without knowing it, even after vaccination. Medical experts including Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID), have cautioned everyone to maintain mask and physical distancing measures even after vaccination so that you don’t unintentionally pass the virus on to others.

So after vaccination, make sure you keep using all of the COVID-19 prevention measures to keep yourself and your community safe.