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.