美国想加拿大所需，开始招募志愿者，进行疫苗混搭试验。
1 hr 40 min ago
US government researchers start testing mix-and-match Covid-19 booster shots
From CNN’s Maggie Fox
Is it okay to use a different brand of vaccine for your coronavirus booster shot? The US National Institutes of Health said Tuesday it is launching a trial to see if it’s safe and if mixing vaccine types works.
The phase 1/2 clinical trial will enroll 150 volunteers who have been fully vaccinated already to see if giving a different type of brand of vaccine gives them the desired immune system boost without side-effects.
It’s not known yet whether people will need booster doses of coronavirus vaccines — or, if so, when they will be needed. It would be easier to give those boosters if people didn’t have to get the same brand or type of vaccine as they got before.
Currently, three vaccines are authorized in the US: two mRNA vaccines, one made by Pfizer/BioNTech and one made by Moderna, and the vaccine made by Johnson & Johnson’s Janssen vaccine arm, which uses a virus called an adenovirus to deliver genetic material that elicits immunity.
People are supposed to get two doses of either Moderna’s or Pfizer’s vaccine, or a single dose of J&J’s, and scientists are not sure if it matters if people get the same brand or even class of vaccine for all the shots. They’re currently supposed to get the same vaccine for both doses – although earlier Tuesday Canada became the first country to say people could get either mRNA vaccine for the second shot, even if they got AstraZeneca’s adenovirus vaccine for their first dose.
People often get annual influenza shots made by different companies and using different technologies from one year to the next.
“Although the vaccines currently authorized by the U.S. Food and Drug Administration offer strong protection against COVID-19, we need to prepare for the possibility of needing booster shots to counter waning immunity and to keep pace with an evolving virus,” Dr. Anthony Fauci, director of the NIH’s National Institute of Allergy and Infectious Diseases, said in a statement.
“The results of this trial are intended to inform public health policy decisions on the potential use of mixed vaccine schedules should booster doses be indicated.”
The trial will be led at Baylor College of Medicine in Houston and the University of Maryland, College Park. “Twelve to 20 weeks following their initial vaccination regimen, participants will receive a single booster dose of the Moderna COVID-19 vaccine as part of the trial,” the NIH said.
“People who have not yet received an FDA authorized COVID-19 vaccine are also eligible to enroll in the trial in a separate cohort. Initially, these volunteers will receive the two-dose Moderna COVID-19 vaccine regimen and will be assigned to receive a booster dose of a vaccine about 12 to 20 weeks later.”
