Association between post-infection COVID-19 vaccination and symptom severity of post COVID-19 condition among patients on Bonaire, Caribbean Netherlands: a retrospective cohort study

ABSTRACT Objectives In this retrospective cohort study, we aimed to investigate symptom severity change following COVID-19 vaccination among post COVID-19 condition (PCC) patients on Bonaire. Methods Symptomatic cases who tested positive for SARS-CoV-2 between the start of the pandemic and 1 October 2021, were unrecovered on the interview day and unvaccinated prior to infection were identified from the national case registry. Patients were interviewed by telephone between 15 November and 4 December 2021 about sociodemographic factors, pre-pandemic health, COVID-19 symptoms and vaccination status. We compared symptom severity change between the acute and post-acute disease phase (>4 weeks after disease onset) of 14 symptoms on a five-point Likert scale for 36 PCC patients having received at least one dose of the BNT162 (BioNTech/Pfizer) vaccine and 11 patients who remained unvaccinated, using separate multiple linear regression models. Results Most common post-acute symptoms included fatigue (81%), reduced physical endurance (79%), and reduced muscle strength (64%). Post-infection vaccination was significantly associated with reduced severity of heart palpitations, after adjusting for acute phase severity and duration of illness (β 0.60, 95% CI 0.18-1.02). We did not find a statistically significant association with symptom severity change for other, more prevalent symptoms. Conclusions Larger prospective studies are needed to confirm our observation in a small study population that post-infection COVID-19 vaccination was associated with reduced severity of heart palpitations among those with this symptom self-attributed to SARS-CoV-2 infection.