INTRODUCTION

Accurately classifying coronavirus disease 2019 (COVID-19) vaccination status is important for studies of vaccine effectiveness, safety, and uptake,1–3 but verifying vaccination status from medical records may be more resource-intensive than obtaining self-reported status. Self-reported vaccination status could be an efficient method for classifying vaccination status for public health research and monitoring if agreement with medical record documentation is high. Recent studies show high agreement between these two sources in the general population.4,5 We assessed agreement between these two sources for COVID-19 vaccination during pregnancy, when information about both receipt and timing is critical to identifying antenatal vaccination.

METHODS

The Epidemiology of Severe Acute Respiratory Syndrome Coronavirus 2 in Pregnancy and Infancy Community Cohort was approved by the Columbia University IRB and enrolled pregnant individuals at three academic centers (New York, New York; Birmingham, Alabama; Salt Lake City, Utah) during August 2020–February 20216; the last pregnancy ended in October 2021. At 2–4 weeks postpartum, participants completed self-administered pregnancy questionnaires. Starting on February 3, 2021, the questionnaire asked participants about COVID-19 vaccine receipt during pregnancy. Sites verified COVID-19 vaccination status using medical records, including electronic medical records (EMR) linked to state or local vaccine registries, a combination of EMR documentation of vaccine administration or state vaccine registry documentation, or participant vaccine cards.

This analysis was restricted to individuals with pregnancies ending on or after February 3, 2021, who responded to vaccine questions. Agreement between self-reported and medical record–reported vaccination status, number of doses, and vaccine type were assessed using Cohen's kappa. Agreement rate was assessed for timing of vaccination.

RESULTS

Overall, 936 enrolled individuals reached end of pregnancy on or after February 3, 2021, and were eligible to receive COVID-19 vaccine questions; 521 of the 936 (55.7%, 30.3–73.7% by site) responded (Appendix 1, available online at https://links.lww.com/AOG/C917). Of the 521 respondents, 456 (87.5%) had their first vaccine dose verified with vaccine registry data or EMR linked to vaccine registry data, 54 (10.4%) using EMR documentation of vaccine administration, and 11 (2.1%) by participant-provided vaccine cards. Overall, 158 of 521 individuals received COVID-19 vaccine (30.3%, 95% CI 26.4–34.5%) based on self-report (n=156) or medical record (n=148). Most participants who self-reported vaccination received their first dose in the workplace (53.2%, 83/156) or a public health clinic (17.9%, 28/156) (Table 1).

Table 1.:

Participant Characteristics

Of 521 participants in this analysis, 509 had concordant vaccination status between sources; 10 self-reported vaccination without medical record agreement, and two had only medical record–documented vaccination. All 10 participants who self-reported vaccine receipt without medical record agreement worked in health care–related industries, suggesting plausible self-reports; six participants reported receiving vaccine through their workplaces.

There was high agreement between self-reported and medical record COVID-19 vaccination status (Kappa coefficient=0.94, 95% CI 0.91–0.98), number of doses, vaccine type, and timing of receipt (range 0.92–0.94) (Table 2).

Table 2.:

Agreement on Coronavirus Disease 2019 (COVID-19) Vaccine Receipt: Self Report Compared With Medical Record (N=521)*

DISCUSSION

We found high agreement between self-report and medical record documentation of COVID-19 vaccination status and other vaccine characteristics during pregnancy, suggesting that self-report may be an acceptable method for ascertaining COVID-19 vaccination during pregnancy. Medical records reported lower vaccination rates than self-report, which may reflect incomplete or delayed documentation in medical records and highlights the importance of timely data transfer between vaccine registries and medical record systems.

This analysis was conducted among individuals willing to participate in COVID-19 research during the early months of COVID-19 vaccine availability, when a primary series of vaccine was recommended. Findings may not generalize to all pregnant individuals or to later pandemic phases when vaccine recall may be less reliable and verification more prone to missing information as booster doses are recommended. Only 55.7% of participants provided information about vaccination; nonresponse was associated with premature questionnaire discontinuation. Nevertheless, we found high agreement between self-report and medical record vaccination status, suggesting that self-reported COVID-19 vaccination status may be valid for identifying COVID-19 vaccination during pregnancy for public health research.

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