The WHO Just Released a Major Warning About This "Dangerous" Vaccine Trend
The agency is advising people against doing this when getting vaccinated.
As of right now, health officials and researchers say the best way to protect yourself against COVID is by being fully vaccinated—which in the U.S. is either two doses of Pfizer or Moderna or one dose of Johnson & Johnson. But experts are still divided on how to produce the greatest levels of immunity against the virus. As Pfizer butts heads with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) over the need for booster shots, health officials around the world are exploring different options for upping vaccine efficacy. Now, the World Health Organization (WHO) is warning against one vaccination practice that's gaining steam.
The practice: mixing and matching COVID vaccines from different manufacturers. Per Reuters, the WHO has advised against getting two different vaccines, as there is currently little to no data available on how safe or effective it is to take different doses.
"It's a little bit of a dangerous trend here. We are in a data-free, evidence-free zone as far as mix and match," Soumya Swaminathan, WHO's chief scientist, said during a press briefing for the organization on July 12.
This warning comes as some countries are making plans to mix vaccines. According to Reuters, Thailand just announced that it will use AstraZeneca shots as the second dose for people who received the Sinovac vaccine in order to increase protection. This will be the first public mix-and-match of a Chinese vaccine and a Western-developed vaccine, per the news outlet.
"This is to improve protection against the Delta variant and build a high level of immunity against the disease," Thailand's Health Minister Anutin Charnvirakul told reporters, adding that the AstraZeneca shot will come three or four weeks after the Sinovac shot.
But the WHO remains unconvinced. "It will be a chaotic situation in countries if citizens start deciding when and who will be taking a second, a third, and a fourth dose," Swaminathan said.
Preliminary research has found that some vaccine mixtures elicit strong protection, however. Early results from a British vaccine study published June 25 in The Lancet journal found that volunteers who received one dose of the Pfizer vaccine and one dose of the AstraZeneca vaccine produced high levels of antibodies and immune cells. But the CDC also advises against mixing and matching vaccines in terms of the two-dose vaccines available in the U.S., Pfizer and Moderna.
"The safety and efficacy of a mixed-product series have not been evaluated. Both doses of the series should be completed with the same product," the CDC says. People are asked to bring their vaccine cards to their appointment in order to ensure they receive a second COVID shot with the same vaccine they received during their first dose.
"In situations where the same mRNA vaccine product is temporarily unavailable, it is preferable to delay the second dose (up to six weeks) to receive the same product than to receive a mixed series using a different product," the CDC states.