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HomeAmerican Journal of Public Healthindex/list_12208_1Vaccine Coverage Across the Life Course in Michigan During the COVID-19 Pandemic

Vaccine Coverage Across the Life Course in Michigan During the COVID-19 Pandemic

Abstract and Introduction


Objectives: To assess the impact of the COVID-19 pandemic on immunization services across the life course.

Methods: In this retrospective study, we used Michigan immunization registry data from 2018 through September 2020 to assess the number of vaccine doses administered, number of sites providing immunization services to the Vaccines for Children population, provider location types that administer adult vaccines, and vaccination coverage for children.

Results: Of 12 004 384 individual vaccine doses assessed, 48.6%, 15.6%, and 35.8% were administered to children (aged 0–8 years), adolescents (aged 9–18 years), and adults (aged 19–105 years), respectively. Doses administered overall decreased beginning in February 2020, with peak declines observed in April 2020 (63.3%). Overall decreases in adult doses were observed in all settings except obstetrics and gynecology provider offices and pharmacies. Local health departments reported a 66.4% decrease in doses reported. For children, the total number of sites administering pediatric vaccines decreased while childhood vaccination coverage decreased 4.4% overall and 5.8% in Medicaid-enrolled children.

Conclusions: The critical challenge is to return to prepandemic levels of vaccine doses administered as well as to catch up individuals for vaccinations missed.


The pandemic spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, exploded onto the global stage in early December 2019 in Wuhan, China.[1] The first confirmed case of COVID-19 in the United States was reported on January 20, 2020,[2] and community transmission was detected in February 2020. By mid-March, all 50 states, the District of Columbia, and all 4 US territories had reported cases of COVID-19.[3] Michigan reported its first case on March 10, 2020, and, soon thereafter, on March 13, 2020, the United States declared a national state of emergency to control the pandemic spread of the virus.[4] As of April 27, 2021, more than 918 000 cases and 17 400 deaths have been recorded in Michigan, and more than 31.9 million cases and more than 569 700 deaths have been reported across the United States.[3]

Public health response measures were implemented across the nation to mitigate the pandemic, centering on social distancing and quarantine policies, including shelter-in-place and stay-at-home orders. Michigan declared a state of emergency[5] and implemented executive orders to suspend in-person operations that were not critical to sustain or maintain life, disrupting access to routine health services.[6,7] Michigan reopened using a tiered approach on June 22, 2021. Public schools, kindergarten through grade 12, also opened for the 2020–2021 academic year through a combination of in-person, online, and hybrid learning.

Core preventive services, including immunizations, were dramatically interrupted resulting in declines in vaccination coverage leaving communities at risk for vaccine-preventable diseases (VPDs) and associated complications.[8,9] With interruptions of immunization services, concerns about outbreaks of disease, particularly measles, which requires an estimated immunity level of at least 92% to 94% to reach the herd immunity threshold and prevent outbreaks, were of primary concern.[10] Reductions in measles coverage and coverage of other routinely recommended vaccines (e.g., diphtheria, mumps, pertussis, polio, varicella, and rubella) threaten herd immunity, particularly in areas where unvaccinated persons are in close proximity and introductions of cases through travel are more likely. The critical challenge for Michigan and other states across the nation is to ensure a return to prepandemic levels of doses administered while ensuring catch-up doses are administered to individuals who have fallen behind on complying with the Advisory Committee on Immunization Practices (ACIP) routine immunization schedules.[11]

To do this, states rely on programs like the Vaccines for Children (VFC) program, a federal safety net that seeks to ensure that all children have access to vaccines without financial barriers. Children eligible for the VFC program include those who are Medicaid-eligible, uninsured, and American Indian or Alaska Native. In addition, children with health insurance that does not cover vaccination (underinsured) can get free vaccines at federally qualified health centers.[12] Furthermore, all states including Michigan utilize pharmacists and pharmacies as vaccinators and sites of service. Pharmacies offer the convenience of extended hours outside of those for a traditional medical clinic, including holidays, expanding access points for routine vaccination services, particularly for adults who value the convenience pharmacies offer.[13] In this retrospective study, we used the Michigan Care Improvement Registry (MCIR; the state’s immunization information system [IIS]) and assessed vaccine doses administered across the life course during the COVID-19 pandemic. We also assessed routine vaccination coverage for children aged 19 to 35 months.[14]

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