'How safe does this make my family member?' What doctors should tell patients about COVID-19 vaccine

COVID-19 vaccine
In a call hosted by the Infectious Disease Society of America, experts said there is not enough evidence to show vaccines would stop a person from transmitting the virus to others. (Getty/Meyer & Meyer)

As more patients get vaccinated against COVID-19, doctors are urged to advise them to continue following safety protocols such as mask-wearing, handwashing and social-distancing, experts said this week. 

In a call hosted by the Infectious Disease Society of America, experts said there is not enough evidence to show vaccines would stop a person from transmitting the virus to others.

So while many are getting anxious to travel or get back to normal activities in public, they need to remain vigilant—even if they're one of the lucky few who've gotten the vaccine. 

"I know that it's hard to hear," said Joshua Barocas, M.D., an infectious diseases physician from Boston Medical Center. "But we are less than 2% vaccinated and only a month and change into the rollout."

Much of what is known about transmission is based on modeling and previous knowledge about virus transmission in general from previous pandemics, he said.

"When we're having these discussions with patients about risk reduction and 'How safe does this make my family member or make it for me to travel?' the vaccine itself on the person who's been vaccinated has incredible effectiveness," Barocas said. 

However, one reason for optimism: results from an Oxford-AstraZeneca vaccine study put forward data this week showing their vaccine could cut transmission by about two-thirds. If that were to continue to bear out across other vaccines, that could mean an unvaccinated person would have some protection from those who have been vaccinated, Barocas said.

But the science isn't there yet, he said. 

"We know vaccines offer true risk reduction. We know they protect a person. They are very good about protecting a person," Barocas said. "We are also starting to gather actual evidence from some of the trials and the retrospective trials on what they do for transmission and what many of us have felt for a while, is they probably decrease transmission. The fact is: we're getting data on that."

Among other insights doctors might want to consider when talking with their patients about the COVID-19 vaccine, the IDSA expert said: 

  • On mask-wearing after getting COVID-19 vaccine: "I still wear a mask," Barocas said. "The reason is because I don't know who else is vaccinated. I don't know who else has risk factors that make them high-risk for serious infection, death, hospitalization or who has high-risk family members. I don't know how far my bubble extends. As a result, it's important for me because I know it doesn't necessarily break the entire chain of transmission." 
  • On double masking: "We haven't seen studies yet," Barocas said. "Anything is better than nothing. If you have two, fantastic." 
  • On the safety-measures impact on flu: "It is one of the silver linings right now that we have not seen a lot of flu or really other seasonal respiratory viruses," Barocas said. "There are probably a number of reasons why we've seen a limited number of influenza cases but one of them has to do most likely with masks. Another has to do with social distancing."