This Vaccine May Protect You Better If You Delay the Second Shot, Study Says
Waiting 12 weeks between shots of this vaccine can boost antibodies.
For the most part, experts have been stern about adhering to the recommended intervals between your COVID vaccine shots if you're doing a two-dose regimen. For Pfizer, you're supposed to wait three weeks between injections, while Moderna requires four weeks. The Centers for Disease Control and Prevention (CDC) has advised that you should only exceed these intervals if "delay is unavoidable," and even then, it should not go past 42 days. However, a recent study found that when people 80 and older delay their second shot of Pfizer, they have more antibodies.
The study was led by the University of Birmingham with Public Health England. The research, published on May 14, found that antibody response in people 80 and over was three and a half times higher when they delayed the second dose of the Pfizer vaccine for 12 weeks, as compared to those who received it at the recommended three-week interval. Additionally, researchers concluded that administering the second dose after 12 weeks can potentially enhance and extend antibody immunity, which plays an essential role in neutralizing the virus and preventing infection.
While the U.S. continues to adhere to the three-week interval and suggests only pushing the second dose to 42 days at most, other countries have stretched the second injection further. On Dec. 30, U.K. Chief Medical Officers released a statement saying the first and second doses of the Pfizer and AstraZeneca vaccines may be taken up to 12 weeks apart.
Although COVID vaccination is well underway, experts still have a lot to learn about the best way to vaccinate for this virus. "Many questions remain regarding [COVID vaccines'] optimal delivery for provision of effective and sustained immunity," study author Helen Parry, PhD, said in the statement. This study was the first to examine the antibody response to the vaccine when it's given after such an extended period of time. "This research is crucial, particularly in older people, as immune responses to vaccination deteriorate with age," Parry added. "Understanding how to optimize COVID-19 vaccine schedules and maximize immune responses within this age group is vitally important."
This study's findings are not only beneficial to people aged 80 and older, but also help inform vaccination efforts in general. "The enhanced antibody responses seen after an extended interval may help to sustain immunity against COVID-19 over the longer term, and further improve the clinical efficacy of this powerful vaccine platform," study co-author Paul Moss, PhD, said in the statement.