Effect of Full Vaccination and Post-Covid Olfactory Dysfunction in Recovered Covid-19 Patient. A Retrospective Longitudinal Study With Propensity Matching

Abstract

Background Symptoms after Coronavirus Disease (COVID-19) infection affect the quality of life of its survivor especially to the special senses including olfactory function. It is important to prevent the disability at an earlier stage. Vaccination as key prevention has been proven to be effective in reducing symptomatic disease and severity. However, the effects of vaccination on post COVID symptoms have not been evaluated. This study aimed to evaluate the possible protection of full vaccination and the occurrence of post-COVID olfactory dysfunction, specifically anosmia, and hyposmia in patients who were diagnosed with COVID-19. Method A longitudinal analysis using the retrospective cohort of the Indonesian patient-based Post-COVID-19 survey collected from July 2021 until December 2021, involving COVID-19 Patients confirmed by Real-Time Polymerase Chain Reaction (RT-PCR) and/or Antigen test. Variables including demography, comorbidities, health behavior, type of vaccine, symptoms, and treatment were collected through an online questionnaire based on the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS). Participants were matched (1:1) using propensity matching score into two exposure statuses, infected 1)>14 days of full vaccination and 2)<14 days or incomplete or unvaccinated. The olfactory dysfunction was assessed two weeks and four weeks after negative conversion with PCR using a self-measured olfactory questionnaire (MOQ). The Generalized Estimating Equation (GEE) was performed to assess the effect of full vaccination on post-COVID-19 olfactory dysfunction. The Receiver Operating Characteristic determined the sensitivity and specificity of the cutoff value of the days from fully vaccinated to diagnosis and the olfactory dysfunction. Results A total of 442 participants were extracted from the cohort and inoculated with the inactivated viral vaccine (99.5%). The prevalence of olfactory dysfunction in two weeks was 9.95% and 5.43% after four weeks. Adjusted by other variables, people who were infected >14 days after being fully vaccinated had a 69% (adjusted Odds Ratio / aOR 0.31 95% CI 0.102-0.941) probability of developing olfactory dysfunction. Longer days of fully vaccinated to infection are associated with increased risk (aOR 1.012 95% CI 1.002-1.022 p-value 0.015). A cut-off of 88 days of full vaccination-to-diagnosis duration has Area Under Curve (AUC) of 0.693 (p=0.002), the sensitivity of 73.9%, and specificity of 63.3% in differentiating the olfactory dysfunction event in two weeks after COVID-19 with a crude odds ratio of 4.852 (95% CI 1.831-12.855 p=0.001) Conclusion After 14 days of full vaccination, the protective effect could reduce the chance of post-COVID olfactory dysfunction although a longer full vaccination-to-diagnosis duration increases the risk. It is important to consider a booster shot starting from 89 days after the last dose in those who received the inactivated viral regimen.

Effect of COVID-19 vaccine on long-COVID: A 2-year follow-up observational study from hospitals in north India

“…UK Health Security Agency [18] published a rapid evidence briefing on the effectiveness of vaccination against long-COVID. In their analysis, six of the 8 studies suggested that vaccinated cases were less likely to develop symptoms of long-COVID in the short term (within 4 weeks after infection), medium term (12 to 20 weeks after infection) and long term (6 months after infection) [4][5][6][7][8]. Antonelli et al [28] found that fully vaccinated patients were almost half as likely to have symptoms lasting ≥ 28 days than unvaccinated patient (OR = 0.51, 95% CI: 0.32 to 0.82, p = 0.005).…”

“…Al–Aly et al [4] reported in their retrospective cohort study that vaccinated cases were less likely to have at least one post-acute sequelae of COVID-19 at 6 months compared with the unvaccinated cases (HR = 0.87, 95% CI: 0.83 to 0.92). A retrospective cohort study by Herman et al [5] found that fully vaccinated patients were less likely to develop of olfactory dysfunction after infection than unvaccinated patients (OR = 0.31, 95% CI: 0.10 to 0.94), but there was little evidence for an association between full vaccination and olfactory dysfunction at 4 weeks after end of infection (P = 0.59). An Israeli study by Koudi et al [6] found that those with 2 or 3 doses of vaccine were 54% to 83% less likely to report 7 of the 10 most commonly reported symptoms than the unvaccinated.…”

Stellenwert der COVID-19-Impfung im Kontext von Long-COVID

“…Tab. 1), wovon 7 zeigen, dass die COVID-19-Impfung mit einem reduzierten Long-COVID-Risiko assoziiert ist, wobei dies in 6 Fällen [19][20][21][22][23][24][25] für die vollständige Impfung und in einem Fall für die Einfachimpfung zutraf [25]. Zwei dieser Studien unterschieden nicht, ob die Impfung vor oder nach Infektion stattgefunden hat [24,25].…”

“…Eine indonesische Studie beschäftigte sich mit Geruchsstörungen nach SARS-CoV-2-Infektion; diese traten 2 Wochen nach Freitesten bei vollständig Geimpften in geringerem Ausmaß auf als in der Kontrollgruppe ("adjusted odds ratio" [aOR] 0,31, 95 %-KI 0,102-0,941), waren allerdings wieder häufiger, je länger der Infektionszeitpunkt von der Impfung entfernt war [21].…”

Vaccination efficacy against post-COVID-19 symptoms in Delta and Omicron waves: a prospective cohort in East Indonesia

“…However, there is limited study on how the different variants affect the occurrence of residual symptoms. For example, a longitudinal study in Indonesia addressed persistent symptoms, including fatigue, chronic cough, and chronic headache within 90 days [8], and the impact of vaccination against specific symptoms, such as olfactory dysfunction [9]. However, these studies did not cover the current period where the Omicron is the most prevalent strain.…”