COVID-19 Vaccination and Bariatric Surgery.

Dear Editor,

We would like to share ideas on “COVID-19 Vaccination and Timing of Bariatric Surgery: Considerations and Concerns for Patients with Severe Obesity [1].” Pazouki et al. noted that “we encourage operating on fully vaccinated patients…… the second shot of the vaccine and the surgery, with more preference for the latter due to its lower likelihood of infection after surgery” [1]. We agree that it is necessary to prevent COVID-19 for the patient. However, we should have a careful consideration for vaccination management. An obese case usually has a high blood viscosity [2], and the COVID-19 vaccine can induce increased blood viscosity [3]. Additionally, after any operation, a change of blood viscosity can occur [4]. Hence, there might be a possible problem of hyperviscosity in an obese subject after vaccination. Based on these factors, the COVID-19 vaccination should be provided before operation. Pre-operation COVID-19 can also help decrease possible COVID-19 infection of the hospitalized patient during pre-operation period. In case that an emergency surgery is required, there must be a good monitoring of complication of post-operation COVID-19 vaccination.