Obesity Blunts Antibody Response to COVID-19 Vaccines: Study

New research being presented at this year's European Obesity Congress (ECO) in Maastricht, the Netherlands on May 4 to 7, suggests that severely obese adults (aged 18 and over) mount a significantly increased immune response weaker to COVID-19 vaccination compared to those with normal weight. The study is by Prof. Volkan Demirhan Yumuk of Istanbul University in Turkey and his colleagues.

The study also found that people with severe obesity (BMI over 40 kg/m2) vaccinated with the Pfizer/BioNTech BNT162b2 mRNA vaccine generated significantly more antibodies than those vaccinated with the CoronaVac (inactivated SARS-CoV-2) vaccine, suggesting that the Pfizer/BioNTech vaccine may be a better option for this vulnerable population.

Obesity After COVID-19

Obesity is a disease that complicates the course of COVID-19, and the antibody response to the SARS-CoV-2 vaccine in obese adults may be compromised. Vaccines against influenza, hepatitis B, and rabies have shown reduced responses in people with obesity.

‘Pfizer/BioNTech linked to more robust antibody response than CoronaVac in people with severe obesity.’

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To learn more, the researchers investigated the post-vaccination antibody responses of Pfizer/BioNTech and CoronaVac vaccines in 124 adults (average age 42 to 63 years) with severe obesity who visited Obesity Center at Istanbul University-Cerrahpasa, Cerrahpaşa Medical College Hospitals, between August and November 2021. They also recruited a control group of 166 normal-weight adults (BMI less than 25 kg/m2, average age 39 to 47 years) attending the Cerrahpasa Hospitals Vaccination Unit.

The researchers measured antibody levels in blood samples taken from patients and normal weight controls who had received two doses of the Pfizer/BioNTech or CoronaVac vaccine and had received their second dose 4 weeks earlier. The participants were classified by infection history, whether or not they previously had COVID-19 (confirmed by their antibody profile).

Results of the Study

Overall, 130 participants received two doses of Pfizer/BioNTech and 160 participants two doses of CoronaVac, of whom 70 had prior SARS-CoV-2 infection.

In those without prior SARS-CoV-2 infection and vaccinated with Pfizer/BioNTech, severely obese patients had antibody levels more than three times lower than normal-weight controls (mean 5,823 vs. 19,371 AU/mL).

Similarly, in participants without prior SARS-CoV-2 infection and vaccinated with CoronaVac, severely obese patients had 27-fold lower antibody levels than normal-weight controls (mean 178 vs. 4,894 AU/mL).

However, in those with prior SARS-CoV-2 infection, antibody levels in severely obese patients vaccinated with Pfizer/BioNTech or CoronaVac were not significantly different from normal-weight controls (mean 39,043 vs 14,115 AU/mL and 3,221 vs 7,060 AU/ml, respectively).

Interestingly, the analyzes found that in severely obese patients, with and without prior SARS-CoV-2 infection, antibody levels in those vaccinated with Pfizer/BioNTech were significantly higher than those vaccinated with CoronaVac.

“These results provide new information on the antibody response to SARS-CoV-2 vaccines in people with severe obesity and reinforce the importance of prioritising and increasing vaccine uptake in this vulnerable group,” says Prof. Yumuk. “Our study confirms that immune memory induced by prior infection alters the way in which people respond to vaccination and indicates that two doses of Pfizer/BioNTech vaccine may generate significantly more antibodies than CoronaVac in people with severe obesity, regardless of infection history. However, further research is needed to determine whether these higher antibody levels provide greater protection against COVID-19.”

Source-Medindia