Association of the COVID-19 Pandemic With Routine Childhood Vaccination Rates and Proportion Up to Date With Vaccinations Across 8 US Health Systems in the Vaccine Safety Datalink

Abstract

Importance: The COVID-19 pandemic has affected routine vaccine delivery in the US and globally. The magnitude of these disruptions and their association with childhood vaccination coverage are unclear.

Objectives: To compare trends in pediatric vaccination before and during the pandemic and to evaluate the proportion of children up to date (UTD) with vaccinations by age, race, and ethnicity.

Design, setting, and participants: This surveillance study used a prepandemic-postpandemic control design with data from 8 health systems in California, Oregon, Washington, Colorado, Minnesota, and Wisconsin in the Vaccine Safety Datalink. Children from age groups younger than 24 months and 4 to 6, 11 to 13, and 16 to 18 years were included if they had at least 1 week of health system enrollment from January 5, 2020, through October 3, 2020, over periods before the US COVID-19 pandemic (January 5, 2020, through March 14, 2020), during age-limited preventive care (March 15, 2020, through May 16, 2020), and during expanded primary care (May 17, 2020, through October 3, 2020). These individuals were compared with those enrolled during analogous weeks in 2019.

Exposures: This study evaluated UTD status among children reaching specific ages in February, May, and September 2020, compared with those reaching these ages in 2019.

Main outcomes and measures: Weekly vaccination rates for routine age-specific vaccines and the proportion of children UTD for all age-specific recommended vaccines.

Results: Of 1 399 708 children in 2019 and 1 402 227 in 2020, 1 371 718 were female (49.0%) and 1 429 979 were male (51.0%); 334 216 Asian individuals (11.9%), 900 226 were Hispanic individuals (32.1%), and 201 619 non-Hispanic Black individuals (7.2%). Compared with the prepandemic period and 2019, the age-limited preventive care period was associated with lower weekly vaccination rates, with ratios of rate ratios of 0.82 (95% CI, 0.80-0.85) among those younger than 24 months, 0.18 (95% CI, 0.16-0.20) among those aged 4 to 6 years, 0.16 (95% CI, 0.14-0.17) among those aged 11 to 13 years, and 0.10 (95% CI, 0.08-0.13) among those aged 16 to 18 years. Vaccination rates during expanded primary care remained lower for most ages (ratios of rate ratios: <24 months, 0.96 [95% CI, 0.93-0.98]; 11-13 years, 0.81 [95% CI, 0.76-0.86]; 16-18 years, 0.57 [95% CI, 0.51-0.63]). In September 2020, 74% (95% CI, 73%-76%) of infants aged 7 months and 57% (95% CI, 56%-58%) of infants aged 18 months were UTD vs 81% (95% CI, 80%-82%) and 61% (95% CI, 60%-62%), respectively, in September 2019. The proportion UTD was lowest in non-Hispanic Black children across most age groups, both during and prior to the COVID-19 pandemic (eg, in May 2019, 70% [95% CI, 64%-75%] of non-Hispanic Black infants aged 7 months were UTD vs 82% [95% CI, 81%-83%] in all infants aged 7 months combined).

Conclusions and relevance: As of September 2020, childhood vaccination rates and the proportion who were UTD remained lower than 2019 levels. Interventions are needed to promote catch-up vaccination, particularly in populations at risk for underimmunization.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Klein reported grants from the US Centers for Disease Control and Prevention (CDC) during the conduct of the study and grants from Merck, Sanofi Pasteur, GlaxoSmithKline, Pfizer, and Protein Science (now Sanofi Pasteur) outside the submitted work. Dr Donahue reported grants from the CDC during the conduct of the study and grants from Janssen Global Services, LLC, for exploratory research related to a non–COVID-19 vaccine outside the submitted work. Dr Jackson has received a research grant from Sanofi Pasteur to study the epidemiology of respiratory syncytial virus. Dr Jackson reported grants from the CDC during the conduct of the study; grants from Sanofi Pasteur outside the submitted work. Dr Qian has received research support from Moderna, GlaxoSmithKline, and Dynavax for unrelated studies. Drs DeSilva, Haapala, and Kharbanda reported grants from the CDC (contract 200-2012-53526) during the conduct of the study. Drs Daley and Henninger reported grants from the CDC during the conduct of the study. Dr Williams reported Vaccine Safety Datalink COVID-19 Infrastructure Funding grants from the CDC during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.. Weekly Vaccine Administration Rates for Included Pediatric Populations

Data are from 8 US health systems in the Vaccine Safety Datalink and are organized by age group (Haemophilus influenzae type B conjugate; pneumococcal conjugate, 13-valent; inactivated polio; measles, mumps, rubella; and varicella-zoster vaccines were standard. In children aged 4 to 6 years, measles, mumps, and rubella; varicella-zoster; diphtheria, tetanus, and acellular pertussis; and inactivated polio vaccines were standard. In children aged 11 to 13 years, human papillomavirus; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; and quadrivalent meningococcal conjugate vaccines were standard. In those aged 16- to 18 years, human papillomavirus and quadrivalent meningococcal conjugate vaccines were standard.

Figure 2.. Proportion of Individuals Up to Date for Routine Childhood Vaccines

Data include 95% CIs. Data are from 8 Vaccine Safety Datalink health systems, among infants, children, and adolescents reaching specified ages in February, May, and September 2019 and 2020. Up-to-date definitions varied by age. At age 7 months, infants must have received 2 hepatitis B; 2 rotavirus; 3 diphtheria, tetanus, and acellular pertussis; 2 Haemophilus influenzae type B conjugate; 3 pneumococcal conjugate, 13-valent; and 2 inactivated polio vaccine doses. At age 18 months, children must have received 3 hepatitis B; 4 diphtheria, tetanus, and acellular pertussis; 3 H influenzae type B conjugate; 4 pneumococcal conjugate, 13-valent; 3 inactivated polio; 1 measles, mumps, and rubella; and 1 varicella-zoster virus vaccine doses. At age 6 years, they must be in receipt of 5 diphtheria, tetanus, and acellular pertussis; 4 inactivated polio; 2 measles, mumps, and rubella; and 2 varicella-zoster virus vaccine doses. At age 13 years, they must have received 2 human papillomavirus; 1 tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; and 1 quadrivalent meningococcal conjugate vaccine doses. At age 18 years, they must have received 2 human papillomavirus; 1 tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; and 2 quadrivalent meningococcal conjugate vaccine doses.

Figure 3.. Proportion of Individuals Up to Date for Routine Childhood Vaccines

Data include 95% CIs. Data originated across 8 Vaccine Safety Datalink (VSD) health systems, among infants, children, and adolescents reaching specified age in February, May, and September 2020, by race and ethnicity. Up-to-date definitions varied by age. At age 7 months, infants must have received 2 hepatitis B; 2 rotavirus; 3 diphtheria, tetanus, and acellular pertussis; 2 Haemophilus influenzae type B conjugate; 3 pneumococcal conjugate, 13-valent; and 2 inactivated polio vaccine doses. At age 18 months, children must have received 3 hepatitis B; 4 diphtheria, tetanus, and acellular pertussis; 3 H influenzae type B conjugate; 4 pneumococcal conjugate, 13-valent; 3 inactivated polio; 1 measles, mumps, and rubella; and 1 varicella-zoster virus vaccine doses. At age 6 years, they must be in receipt of 5 diphtheria, tetanus, and acellular pertussis; 4 inactivated polio; 2 measles, mumps, and rubella; and 2 varicella-zoster virus vaccine doses. At age 13 years, they must have received 2 human papillomavirus; 1 tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; and 1 quadrivalent meningococcal conjugate vaccine doses. At age 18 years, they must have received 2 human papillomavirus; 1 tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; and 2 quadrivalent meningococcal conjugate vaccine doses.