Declining antibody levels may mean overweight adults have a greater need for a COVID-19 vaccine booster dose, according to a new study. File photo by Debbie Hill/UPI | License Photo
May 19 (UPI) -- Adults at higher weights may have a greater need for COVID-19 vaccine booster doses because they experience sharper declines in virus antibody levels after they receive the first two shots than those who maintain a healthy weight, a study published Thursday found.
Among 50 participants, those who weigh 120 pounds or more had up to 20% lower virus antibody levels six months after getting their second dose of the Pfizer-BioNTech vaccine than those who weighed less, the data published Thursday by JAMA Network Open showed.
With each roughly 22-pound increase in weight, antibody levels at six months declined by an additional 5% in women, the researchers said.
Based on the findings, "we recommend a booster dose to overweight persons around six months after the second dose," study co-author Dr. Su Youn Nam told UPI in an email.
However, "the booster dose may be applied later than six months after the second dose in young and middle-aged healthy persons with low body weight," said Nam, an assistant professor of internal medicine at Kyungpook National University in Daegu, South Korea.
The findings are based on an analysis of antibody levels in 50 health workers ages 25 to 45 years who received two doses of the Pfizer-BioNTech vaccine in South Korea.
Study participants weighed between 93 and 202 pounds, so while some were overweight, they were not obese, the researchers said.
Although the Moderna COVID-19 vaccine -- which along with the Pfizer-BioNTech is recommended for use in the United States -- has a similar formulation, weight-associated changes in antibody levels may not occur with it, as well, Nam said.
However, a study published earlier this month found that the Pfizer-BioNTech and another, called CoronaVac, which is not approved for use in the United States, produced fewer antibodies in obese adults.
Previous research has suggested that the flu shot is less effective in obese adults.
Nearly three in four adults in the United States are overweight or obese, according to the Centers for Disease Control and Prevention.
Still, while two-thirds of the population has been fully vaccinated as of Wednesday, fewer than half of those eligible have received a booster dose, the agency reports.
"The participants in this study are lean, normal or overweight persons, not obese," Nam said.
"Therefore, we cannot comment for obese persons," he said.