Your questions, answered "My son and his wife, who live in China, may be able to visit soon now that international travelers who have had WHO-approved vaccines can travel to the US. They've had one each of the Sinovac and Sinopharm vaccines (standard protocol in their province) - which booster should they get in the US, if they'd like?" — Beth in Massachusetts After nearly two years, the U.S. government is rolling back travel restrictions. Starting Monday, vaccinated visitors from China and dozens of other countries barred from entry for most of the pandemic will be able to come to the United States. What a relief for families like yours. If your son and his wife decide to seek out a booster while they're here, they should talk with a medical professional first about whether it's a good idea and what shot they might get. The advice may vary depending on when they received their doses and how long they'll be in the United States. This is something many travelers are likely to consider now that the United States is reopening its borders. "Vaccine tourism" was already popular here even with the restrictions in place. Some cities became vaccine destinations — over the summer, San Francisco's airport said thousands of travelers had gotten jabs at its in-house clinic. During the early months of the vaccine rollout, some states offered the shots only to residents. But most of those requirements have since been lifted, and the vaccines are plentiful. Americans living abroad will have no trouble making appointments here. Foreigners probably won't face any serious hurdles, either. But visitors from China and other countries that administer Sinovac and Sinopharm should bear in mind that not much data exists on the safety or efficacy of mixing those vaccines with the shots authorized in the United States. Sinovac and Sinopharm use a different technology than the U.S. coronavirus vaccines, deploying a deactivated virus to tell the immune system how to fight covid-19. Flu shots work the same way. The Pfizer-BioNTech and Moderna vaccines use molecules called mRNA to provoke an immune response, while the Johnson & Johnson shots use a harmless virus called an adenovirus. "We don't know the safety of of these mix-and-match approaches [involving Sinovac and Sinopharm] but there's no theoretical concern I'd have other than we don't have the data," said Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston. A World Health Organization advisory group said this month that Sinovac and Sinopharm recipients over 60 should get a third dose of their current vaccine, noting that a different shot could be "considered" depending on availability. And Turkey has offered Pfizer boosters to Sinovac recipients. But no U.S. health agency has offered guidance on possible combinations of these vaccines. That doesn't mean it's dangerous — mixing different vaccine types might offer some immune benefits — but we just don't have a clear picture on this particular approach yet. | 
Email 
