A combination of AstraZeneca and Pfizer doses results in a stronger immune response than two doses.This is based on early data from a UK study. However, it has not been peer reviewed.Experts believe it would be beneficial to obtain an mRNA booster following J&J's single dose shot.Subscribe to the Insider Healthcare Newsletter for the most recent healthcare news and analysis sent straight to your inbox Loading Click Sign up to receive marketing emails and other offers from Insider.There is increasing evidence to support a mix-and match approach to coronavirus shots.Although not yet peer-reviewed, early data from a UK study suggests that mixing AstraZeneca and Pfizer vaccines results in a stronger immune response than two doses. Researchers measured the antibody levels in 830 volunteers who were given either two doses of the vaccine or a combination of Pfizer/AstraZeneca four weeks apart.Volunteers who received AstraZeneca followed by Pfizer had nearly the same antibody levels as those who received Pfizer twice. The antibody levels of volunteers who received AstraZeneca's first shot and Pfizer's second shot were slightly lower than those who received the reverse combination. These levels were five times greater than the antibody response to AstraZeneca after receiving two doses.Deborah Dunn-Walters from the University of Surrey said that mixing the two vaccines is safe and can increase the immune response.However, there are caveats. The UK study only examined immune-system responses and not real-world infection rates. Research has also shown that AstraZeneca vaccines work better when administered 12 weeks apart. The UK team has started a separate study based on this interval. However, those results are still not available.Experts believe it may be beneficial for those who have received an earlier shot to get a booster shot.Paul Hunter, a University of East Anglia medicine professor, stated in a statement that "from this study, people having had a first dose of AstraZeneca ought probably to be offered the Pfizer vaccine or possibly Moderna/Novavax dependent upon the future trial data out of this study"He said that people who have had a Pfizer course first may not require an autumn booster. But if they do, it doesn't matter what vaccine they receive.Some countries allow residents to mix and match.Chanei Henry is the senior research coordinator for molecular microbiology and molecular virusology at Baylor College of Medicine. She prepares a COVID-19 vaccination. Baylor College of MedicineResearch has shown that mixing and matching vaccines can produce better results than single vaccines. This was even before the coronavirus vaccines were developed. Johnson & Johnson's Ebola vaccine uses, for example, an adenovirus shot and a modified poxvirus. Researchers have also tested other vaccine combinations for future HIV shots.Some countries allow residents to mix and match coronavirus vaccinations.Canada had earlier this month announced that Moderna and Pfizer shots could be interchangeable due to the low supply of vaccines in the country. A number of European countries, including France, Spain and Germany, have announced that those who have received AstraZeneca can switch vaccines for the second dose. This is due to reports of rare blood clots.Side effects are still a concern. In the UK, volunteers who received a combination of Pfizer/AstraZeneca had higher rates of muscle pain, chills, headaches and nausea than those who had received two doses of the vaccine. A Spanish study found that only one dose of AstraZeneca's vaccine was sufficient to cause mild or moderate side effects.Another mix-and match study funded by the National Institutes of Health is offering participants a booster of Moderna’s vaccine following their initial regimen of Moderna or Johnson & Johnson.Joseph Hyser, who was a participant in the trial, said that his side effects after Moderna's booster were more severe than those he experienced after his previous doses of Pfizer vaccine. He described feeling like he had done a rigorous workout the day before his booster, with chills and soreness in his arms that felt like he'd been hit in the shoulder.The NIH study could provide much-needed insight into whether J&J's single dose shot with a Moderna booster provides similar protection as a two-dose mRNA vaccination. Some experts are eager to get J&J's shot. Angela Rasmussen is a University of Saskatchewan virologist who tweeted Tuesday that she had received the Pfizer vaccine to "top-off" the J&J vaccination she received in April.Rasmussen advised people who had J&J's shots to talk with their healthcare providers about getting an additional dose.She wrote, "We shouldn’t wait to make suggestions about this."Reporting was contributed by Hilary Brueck, Dr. Catherine Schuster Bruce.
