Vaccination rarely changes persistent post-COVID smell and taste symptoms

An international observational survey found that COVID-19 vaccination was associated with little change in smell or taste among most people with persistent sensory symptoms following infection. Researchers surveyed 1,352 vaccinated participants across 52 countries between May 2022 and August 2023; about half said they had experienced changes in smell or taste after contracting COVID-19. For more than 90% of participants, vaccination was followed by no change in these symptoms, while reports of improvement were uncommon overall and worsening was relatively uncommon among those with symptoms such as parosmia, phantosmia or distorted taste.

The study was led by Daniel Hwang of the University of Queensland’s Institute for Molecular Bioscience and conducted through the Global Consortium for Chemosensory Research. Investigators described the study as an attempt to examine anecdotal reports from a Facebook support group that some people experienced better smell after vaccination. Participants completed a multilingual survey, enabling the team to examine self-reported sensory changes in a geographically broad population. The analysis distinguished among different forms of chemosensory dysfunction rather than treating all symptoms as a single loss of smell or taste. These included parosmia, in which familiar odors become distorted; phantosmia, in which people smell things that are not present; and distorted taste.

Although the large majority reported no post-vaccination change, some participants said their symptoms improved after vaccination. The researchers said these reports may provide reassurance for people with persistent post-COVID sensory problems who are concerned that vaccination could worsen their condition. They also emphasized that the survey cannot establish that vaccination produced the reported improvements. Because the research was observational, natural recovery from COVID-related smell and taste problems may have contributed to the pattern. The findings therefore support an association between vaccination and mostly stable symptoms, not a causal conclusion that the vaccine altered chemosensory function in most participants.

Persistent changes in smell and taste can affect eating, nutrition, enjoyment of food and quality of life after COVID-19. The study authors said clinicians should assess different types of smell and taste dysfunction separately when counseling patients, because conditions such as parosmia and phantosmia may follow different courses. The survey results provide evidence that vaccination was not commonly followed by deterioration or improvement in the symptoms reported by this group, but its design does not determine why individual experiences differed. Earlier evidence cited in the release indicates that these symptoms have varied across the pandemic: a 2020 systematic review and meta-analysis of more than 38,000 people estimated that 43% experienced smell dysfunction and 45% experienced taste dysfunction, while a 2023 study reported a global prevalence of smell dysfunction of 3.7% with later variants. A 2025 review estimated that about 7% of participants experienced loss of smell three years after infection, underscoring the continued burden of persistent chemosensory problems.

Subject of Research: An observational survey of post-vaccination changes in smell and taste among people with persistent symptoms after COVID-19

Article Title: Vaccination has little impact on post-COVID smell and taste issues

Article References: Vaccination has little impact on post-COVID smell and taste issues. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: COVID-19 vaccination, loss of smell, loss of taste, parosmia, phantosmia, chemosensory dysfunction, post-COVID symptoms, observational study, global survey, Vaccination, little, impact