A coronavirus vaccine will likely be less effective in people who are obese, scientists say. Vaccines for other diseases including influenza, tetanus, rabies, and hepatitis B have been shown to be less effective among obese people, a pattern that researchers say will likely continue with the vaccine scientists around the world are scrambling to deliver. “Will we have a Covid vaccine next year tailored to the obese? No way,” Raz Shaikh, a nutrition associate professor at the University of North Carolina Chapel Hill, said. “Will it still work in the obese? Our prediction is no.” The issue is particularly of concern in the United States, where more than 107 million Americans are obese. Those with a body mass index over 30 are among those at the greatest risk of experiencing severe COVID-19 symptoms. This group encompasses about 42 percent of American adults.