Association between History of Vaccination and Symptoms at Diagnosis of Coronavirus Disease 2019

INTRODUCTION: We investigated the association between history of vaccination for coronavirus disease 2019 (COVID-19) and symptoms at its diagnosis. METHODS: We retrospectively analyzed 2566 consecutive individuals suspected of having COVID-19 and visited a designated clinic between January and September 2022 (1733 were diagnosed with COVID-19, and 816 tested negative for COVID-19) in Japan. The individuals were divided by vaccination history for COVID-19. RESULTS: In the COVID-19-free individuals, the vaccination was not significantly associated with any symptoms. Contrarily, those with COVID-19 demonstrated an inverse relationship between the vaccination and body temperature; the adjusted mean value was higher by 0.01°C, 0.04°C, 0.09°C, 0.27°C, and 0.34°C and 0.48°C in individuals vaccinated 2-4, 4-6, 6-8, 8-10, and >10 months before and those unvaccinated, respectively, than in those vaccinated within 2 months (P = 0.96, 0.41, 0.081, 0.006, 0.004, and <0.001). Furthermore, among the affected population, individuals vaccinated long before or never vaccinated more frequently complained of fatigue and headache; the adjusted odds ratios of those vaccinated >10 months before and those unvaccinated compared with those vaccinated within 2 months were 2.53 and 2.45 for fatigue and 2.53 and 2.17 for headache (all P < 0.05). Contrarily, the prevalence of rhinorrhea, sore throat, and cough was higher in recently vaccinated individuals (adjusted odds ratios of those vaccinated within 2 months versus those unvaccinated, 2.40, 2.46, and 2.46; all P < 0.05). CONCLUSIONS: Symptoms at the COVID-19 diagnosis differed with the vaccination history. Information on vaccination history would be worth using when suspecting COVID-19 based on symptoms.