Oral side effects of COVID-19 vaccine

Sir, vaccine hesitancy (VH) is an emerging public health challenge nourished by misinformation. Last year, a national cross-sectional survey-based study found out that aversion to the potential side effects of vaccines was the most frequent cause for VH among population groups in the UK.¹ The oral side effects following the administration of vaccines like polio and diphtheria were inconsistently reported with a low level of confidence; they have never been reported independently, eg they emerged typically in conjunction with other dermatologic and systemic symptoms.² The oral side effects of non-orally administered vaccines including influenza vaccine are extremely rare. By looking up grey literature, I have found only one study where only three participants (9%) who received the influenza vaccine got oral side effects associated with flu-like symptoms, thus implying that no statistically significant relationship could be established.³ Owing to the mass vaccination strategies of COVID-19, dentists among other clinical specialists are supposed to provide care to the recently vaccinated patients - at this moment, Hill's criteria of causal inference and rigorous anamnestic recording should be strictly followed before jumping to irrelevant conclusions.