The COVID-19 vaccines from Pfizer and Moderna claim to be over 90% effective in preventing disease, but experts say you should still wear a mask even if you are inoculated.

That is because the pharmaceutical companies tracked people who became ill after they got vaccinated in clinical trials, and not asymptomatic individuals. Research shows as many as 30% of people with COVID-19 show no symptoms, and could be silent spreaders.

According to The New York Times, Michal Tal, an infectious disease specialist at Stanford University, says “a lot of people are thinking that once they get vaccinated, they’re not going to have to wear masks anymore,” adding it is critical people continue donning face coverings since they still could be contagious.

Another reason to be cautious is intramuscular vaccines, like the Pfizer and Moderna candidates, stimulate the entire immune system to produce antibodies that pool throughout the body and might not deposit enough antibody warriors in the nasal passages where the virus likely enters and spreads. Nasal, or mucosal vaccines, are superior to thwarting respiratory viruses, according to the Times.

Experts say the next generation of COVID-19 vaccines could be more targeted to producing immunity in the nose and the rest of the respiratory tract.

According to Chron.com, Dr. David Callender, president and CEO of Texas-based Memorial Hermann Health System, said a vaccine will not be the answer to the COVID-19 pandemic just yet.

Dr. Callender stressed the need to continue precautionary measures such as wearing masks and social distancing until the vaccine becomes widely available.

“We need to continue to use these precautions,” he told Chron.com. “It will take time for the vaccine to be distributed, administered, and then for the immunity to develop in significant numbers of the population.”

This content was originally published here.