Early epidemiological data has shown that obesity is an important risk factor for those infected with SARS-CoV-2. Boston researchers have now provided a more in-depth look at this population in order to assess whether obesity increases susceptibility to infection. The subjects of this study were employees at the Space Exploration Technologies Corporation (SpaceX)—a total of 4,469 participants (53 percent) were enrolled out of a possible 8,400 across seven work sites in four US states (California, Texas, Florida, Washington). Covid-19 status was unknown at the time of enrollment and serial blood sampling was performed monthly during the study period from April to July, and symptoms were also recorded.
One of the main aims of the study was comparing relative body mass index (BMI) and seropositivity (the presence of antibodies indicating a prior infection). The mean BMI of all surveyed was just over 27, which is considered "overweight." Most participants were normal weight (~40 percent) or overweight (~36 percent) and almost 1 in 4 met criteria for obesity (~24 percent). Only 7 percent of subjects had detectable antibodies (IgG) against SARS-CoV-2, the marker indicating an immune response to the covid-19-causing virus. Of these 322 seropositive people, five required hospitalization (~2 percent). Seropositivity was seen to a greater degree with employees in Texas and Hispanic employees.
Obesity was found to have an association with increased symptoms among those with covid-19, especially fever, in mild infections. But interestingly, the authors did not find an increased susceptibility to acquiring SARS-CoV-2 infection, suggesting that there is no evidence of immunosuppression occurring among this population.
While this paper appears in the preprint server medrxiv.com and has therefore not been subject to peer review, the work was performed by a large team of well-respected researchers. The inclusion of SpaceX CEO Elon Musk as a one of around thirty co-authors of this manuscript does not appear to have had any detrimental effect on its quality, despite his consistent and well-documented history of spreading misinformation about covid-19 on Twitter and elsewhere. Those reservations aside, the results exhibited in this manuscript appear to show that once ill, obesity remains an important risk factor in morbidity and mortality, though simply being obese does not put one at a greater risk of contracting the virus in the first place.