Are vaccines safe in patients with Long COVID? A prospective observational study.

Arnold, D. T.; Milne, A.; Stadon, L.; Maskell, N. A.; Hamilton, F. W.

Introduction: Although the efficacy of SARS-CoV-2 vaccination to prevent symptomatic COVID-19 is well established, there are no published studies on the impact on symptoms in patients with Long Covid. Anecdotal reports have suggested both a potential benefit and worsening of symptoms post vaccination with the uncertainty leading to some vaccine hesitancy amongst affected individuals. Methods: Patients initially hospitalised with COVID-19 were prospectively recruited to an observational study with clinical follow-up at 3 months (June-July 2020) and 8 months (Dec 2020-Jan 2021) post-admission. Participants who received the Pfizer-BioNTech (BNT162b2) or Oxford-AstraZeneca (ChAdOx1 nCoV-19) vaccine between January to February 2021 were identified and matched 2:1 (in terms of 8-month symptoms) with participants from the same cohort who were unvaccinated. All were re-assessed at 1 month post vaccination (or matched timepoint for unvaccinated cohort). Validated quality of life (SF-36), mental wellbeing (WEMWBS) and ongoing symptoms were assessed at all timepoints. Formal statistical analysis compared the effect of vaccination on recent quality of life using baseline symptoms, age, and gender in linear regression. Results: Forty-four vaccinated participants were assessed at a median of 32 days (IQR 20-41) post vaccination with 22 matched unvaccinated participants. Most were highly symptomatic of Long Covid at 8 months (82% in both groups had at least 1 persistent symptom), with fatigue (61%), breathlessness (50%) and insomnia (38%) predominating. There was no significant worsening in quality-of-life or mental wellbeing metrics pre versus post vaccination. Nearly two-thirds (n=27) reported transient (<72hr duration) systemic effects (including fever, myalgia and headache). When compared to matched unvaccinated participants from the same cohort, those who had receive a vaccine had a small overall improvement in Long Covid symptoms, with a decrease in worsening symptoms (5.6% vaccinated vs 14.2% unvaccinated) and increase in symptom resolution (23.2% vaccinated vs 15.4% unvaccinated) (p=0.035). No difference in response was identified between Pfizer-BioNTech or Oxford-AstraZeneca vaccines. Conclusions: Receipt of vaccination with either an mRNA or adenoviral vector vaccine was not associated with a worsening of Long Covid symptoms, quality of life, or mental wellbeing. Individuals with prolonged COVID-19 symptoms should receive vaccinations as suggested by national guidance.