Sir, in February 2021, Marouf et al. discovered a strong association between periodontitis and severity of COVID-19 infection with 568 patients.1Shamsoddin used the same data from the Hamad Medical Corporation (HMC) in the state of Qatar for confirmation of the Marouf et al. study and supported its conclusions.2 However, Shamsoddin suggested that a more rigorous methodology, an unbiased approach, and studies on a broader scale (external validity, generalisability) would be needed to clarify the relationship between periodontitis and COVID-19.2

Meta-analyses of epidemiological studies have shown that patients with periodontitis are more likely to have a more severe course of COVID-19.3 Current evidence suggests that this association can be explained by the direct role of periodontitis in exacerbating pulmonary infections and the indirect effect of periodontitis in triggering systemic inflammation and priming the immune system to increase the response to severe COVID-19 infection.4 Mishra et al. showed that the probability of developing severe COVID-19 was 2.81 times higher in patients with periodontitis. There is an association between periodontitis and severe COVID-19.5

The existing studies showed that periodontitis is strongly associated with increased risk of intensive care unit (ICU) admission and increased blood levels of biomarkers associated with poor prognosis. The result suggested that while it is wise not to get COVID-19, it is wiser to reduce periodontitis with regular oral care.