Syringe boxes for Covid-19 vaccines from Pfizer BioNtech and Moderna Inc. in Tucson, Arizona, USA, on Friday, January 15, 2021.
Cherry Orr | Bloomberg | Getty Images
The Centers for Disease Control and Prevention have quietly changed their guidelines on Covid-19 vaccines, saying it is now OK to mix Pfizer and Moderna injections in “exceptional situations” and that it is also okay to wait up to six weeks to get the second two-dose immunization injection from either company.
Although Pfizer and Moderna vaccines, which use messenger RNA technology, were allowed to be administered 21 and 28 days apart, respectively, the agency now says you can receive any of the vaccines, as long as they have at least 28-day break, according to the new guidance posted on its website on Thursday.
Although “every effort” must be made to ensure that a patient receives the same vaccine, in rare situations “any available COVID-19 mRNA vaccine can be administered within a minimum of 28 days between doses” – if supplies are limited or the patient does not know which vaccine they originally received, says the new CDC guidance.
The CDC says the two products are not interchangeable and acknowledged that it had not yet studied whether their new recommendations would change the safety or efficacy of either vaccine.
The agency said health professionals should give patients a vaccination record card that tells them when they received their first injection and what type of injection was done, to help ensure that patients know which injection they should receive the second time. The agency also recommends that providers enter the patient’s vaccination information into their medical records and the government’s immunization information system.
Both companies require two doses to obtain maximum protection against the coronavirus. Although both injections must be administered according to the originally recommended guidelines, the CDC said the second dose of vaccine from either company could be delayed for up to six weeks, if necessary.
The updated guidance occurs when some cities and counties across the country are canceling vaccination appointments because they do not have as many doses as they originally expected.
Wayne County, Michigan, for example, said last week that it would prioritize ensuring that people who get the first chance get the second one on time. But the county said it had to cancel nearly 1,400 appointments so that people had the first chance.
“The intention is not to suggest that people do something different, but to provide doctors with flexibility for exceptional circumstances,” said CDC spokesman Jason McDonald in an email to CNBC.
Dr. Nancy Messonnier, director of the CDC’s National Center for Immunizations and Respiratory Diseases, was asked on Friday about the interval at which the two injections should be administered.
“The data we have is about a two-dose vaccine on the recommended schedule, 21 or 28 days,” she said at a virtual event organized by the Harvard School of Public Health TH Chan and National Public Radio. “At this point, we at the CDC agreed with what the FDA said and the FDA made it very clear that we should use the approved regime.”
“It is solidly rooted in the science and evidence available, and doing something different than that would be to not follow science and potentially not allow us to really realize the full potential of these vaccines,” she added. “So for now, from the CDC perspective, we think there should be two doses in the recommended schedule.”