Obesity is a major public health problem worldwide and has been recognized as one of the most important risk factors for intensive care unit treatment of patients with COVID-19 infection.
The doctors of the Therapeutic Clinic of the Medical School of the National and Kapodistrian University of Athens, Theodora Psaltopoulou, Ioannis Danasis and Thanos Dimopoulos (Rector of EKPA) summarize the relevant data from the publication of Heidi Ledford in the journal Nature- Nature (Nature489, 2020) ) on 20/10/20.
Compared to those with a normal weight for their gender and age, obese patients with COVID-19 are at greater risk of ending up with the disease, having received other risk factors such as diabetes and hypertension. This group of patients often has difficulty in intubation due to the body type, and decreased pulmonary reserves also occur. In addition, adipose tissue highly expresses the receptor of the angiotensin type 2 (ACE2) conversion enzyme through which the SARS-CoV-2 virus enters human cells and so adipose tissue can function as a “reservoir” of high viral load. In addition, excess fatty tissue leads to a state of long-term inflammation that can facilitate the appearance of cytokine storm syndrome, while at the same time weakens the immune response to SARS-CoV-2. It is also worth noting that obesity has been associated with changes in the microbiome of the intestine, nose and lungs.
In particular, obese people have a smaller variety of microbial populations compared to people with normal BMI. Changes in the microbiome may be related to a different degree of immune response to influenza vaccination (Hagan, T. et al. Cell 178, 1313–1328 (2019)). More and more scientists are raising concerns about the expected efficacy of vaccines against SARS-CoV-2 in citizens with a high body mass index.
On the other hand, there is a section of the scientific community that claims that data on the ineffectiveness of the influenza vaccine in obese people are limited and that the generalization of the effects of the influenza vaccine on the SARS-CoV-2 vaccine is not considered completely valid.
In any case, the issue is of great concern, and vaccination with additional booster doses of the vaccine has been proposed if this does not raise the expected immune response in people with obesity. Of particular importance is the appropriate design of clinical studies in order to have the required statistical power to highlight differences between obese and non-obese participants. Many of the current clinical studies are not certain to provide us with the expected quality of the data in order to draw safe conclusions about this, this is why it is necessary to ensure the representative participation of people with increased BMI in the studies in order to be able to benchmark the results.
In conclusion, the percentage of the obese population in some countries reaches 40%, while obese patients with COVID-19 have a significantly higher risk of developing serious illness, complications and death. In this scenario, clarifying the safety and efficacy of vaccines against SARS-CoV-2 in this population group is really important for public health.