An observational study of adverse drug reactions to COVID-19 vaccines reported to the New Mexico poison center hotline.

INTRODUCTION
Post-marketing data on coronavirus vaccines are limited. This study evaluated adverse reactions reported to a statewide hotline after the administration of a coronavirus disease-2019 (COVID-19) vaccine.


METHODS
We collected reports between 1 December 2020 through 30 August 2021 of any individual 12 years of age and older who received an FDA EUA-approved vaccine and experienced an adverse reaction. For each case, we collected vaccine brand, demographics, adverse reaction type, severity, onset of reaction, duration, and outcome. Relative risk analyses were conducted to investigate factors associated with vaccine adverse reactions.


RESULTS
638 adverse drug reaction cases were recorded. The majority identified as female (70.8%) and the median age was 56. Implicated brands were Pfizer BNT162b2 (46.6%), Moderna mRNA-1273 (43.41%), and Janssen Ad26.COV2.S (8.78%). Although the lowest number of cases was with Janssen, this vaccine had the highest incident rate based on reactions per 100,000 doses. Adverse reactions with the highest incidence were systemic reactions (92.7%), injection-site reactions (8.5%), and local non-injection-site reactions (10.4%), with most judged as minor severity. Relative risk was higher for Moderna compared to Pfizer for injection-site non-severe (RR 2.01) and injection-site severe (RR 1.94) reactions. Janssen had a higher risk of headache, dyspnea, and vision changes compared to Pfizer, and a higher risk of headache compared to Moderna. The relative risk for fever, chills, and lymphadenopathy was higher for the second dose than the first dose for all patients.


CONCLUSION
This observational study analyzing adverse drug reactions of the COVID-19 vaccine found that most complaints concerned systemic reactions. We found reaction differences among vaccine brands, between first and second doses for some effects, and selected recurrent events. Poison control centers are uniquely positioned to conduct post-marketing surveillance for the new vaccines as they are available 24/7 to the public and are healthcare providers. Further post-marketing studies are essential to provide a holistic safety profile of COVID-19 vaccines.