RELATED: This One Vaccine Could End the COVID Pandemic, Experts Say. The latest insight comes from data analysis conducted by the Harvard Medical School-affiliated Computational Epidemiology Lab at Boston Children’s Hospital to determine how much of the vaccinated population would be eligible for COVID-19 booster shots based on current CDC guidelines. Besides those aged 65 or older who received their shots six months ago, eligibility also covers anyone at high risk for COVID-19, including those with certain medical conditions—such as being overweight or diagnosed with depression—and those working in certain professions such as healthcare or education. With CDC data finding that 75 percent of the population over the age of 20 is defined as overweight, the combined total means that at least 89 percent of fully vaccinated people are already eligible for their third shot of vaccine, CNN reports.ae0fcc31ae342fd3a1346ebb1f342fcb Even then, the research team estimated that the actual number would likely be even higher since people with underlying conditions and in high-risk professions are already more likely to be fully vaccinated. “That’s even more than I thought,” William Schaffner, MD, a member of the CDC’s Advisory Committee on Immunization Practices, told CNN. “I would have thought it was something like half the population.” The researchers also pointed out that their findings also included the 15 million Americans who had received the single-shot Johnson & Johnson vaccine. Those vaccinated patients have been deemed eligible to receive a booster shot two months after their initial dose. Comparatively, over 175 million people have received two dose shots of either the Moderna or Pfizer mRNA-type vaccines, according to CNN. Schaffner explained that many might be surprised by the number since most officials have been focusing on other less common health issues, even though being overweight has been listed on the CDC’s high-risk list since March. “People were focused on classical underlying conditions, like heart disease, lung disease, diabetes—I think that was principally the mindset of my colleagues,” Schaffner told CNN. RELATED: Dr. Fauci Says He Would Take This COVID Precaution “In a Second”. The findings come as other virus experts have recently come forward with explanations that current booster eligibility requirements aren’t actually as strict as they sound. “The guidelines are unnecessarily complex, but there is a fair degree of latitude,” David O’Connor, PhD, a pathology professor at the University of Wisconsin, told Business Insider. Simply put, the confusion over requirements makes it likely that more fully vaccinated people are eligible to get a booster than they realize. “If you think about it, and you read what the CDC says, there’s a lot of people basically that should get boosters,” Bernadette Boden-Albala, MPH, director of the University of California, Irvine’s public-health program, told Business Insider, adding that “the majority of people are going to meet one of the criteria.” According to researchers who conducted the Children’s Hospital analysis, much of the confusion is because the CDC has used confusing language to distinguish who “may” get a booster and who “should” get a booster. Currently, guidelines dictate that the only people who “should” receive a booster are those 65 and older, those aged 54 to 64 with underlying medical conditions, those 18 or older who are under long-term medical care, and anyone who received the single-dose Johnson & Johnson vaccine two months ago. The agency becomes more vague when describing who “may” get the vaccine, saying that people between 18 and 49 who received Moderna or Pfizer vaccines at least six months ago can make the decision “based on their individual risks and benefits.” For more COVID news sent straight to your inbox, sign up for our daily newsletter.  “The difference between should and may is a pretty important distinction,” Grace Lee, MD, a member of the CDC’s vaccine advisory committee and a pediatrician at the Stanford University School of Medicine, told CNN. “When you’re in the ‘may’ category, you have to look at what applies to your individual situation.” “This is the most complex set of recommendations we’ve had to give,” Lee added. “I can see 100 percent why this is confusing to the general public.” RELATED: If You Get the Pfizer Booster, This Is How Protected You Are From Delta.