RELATED: This Is How Much the Moderna Vaccine Really Protects You, New Study Says. 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.ae0fcc31ae342fd3a1346ebb1f342fcb 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. RELATED: For more up-to-date information, sign up for our daily newsletter. 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. RELATED: Pfizer’s Vaccine Protects You for at Least This Long, Study Finds.