skip to Main Content

Updated Analysis Finds Sustained Drop in Routine Vaccines Through 2020

  • This page as PDF


In 2020, the COVID-19 pandemic resulted in nationwide lockdowns and restrictions with a well-documented impact on utilization of routine healthcare services.

Part of this decline in routine healthcare services occurred in vaccine administration. In February 2021, Avalere released findings from a claims-based analysis that showed significant decreases in claims submissions for Advisory Committee on Immunization Practices (ACIP)-recommended vaccinations across commercial, Managed Medicaid, Medicare Advantage, and Medicare Fee-for-Service (FFS) Part B markets from January to August 2020 when compared to the same period in 2019. The analysis found that claims for recommended vaccines dropped precipitously in March and April 2020, relative to March and April 2019, following the declaration of the COVID-19 public health emergency (PHE). While 2020 vaccine claims increased gradually among adolescents and adults into August 2020, they continued to remain below 2019 levels.

To follow the pandemic’s continued impact on routine immunization, Avalere conducted a follow-up analysis comparing vaccine claims submitted September–November 2020 to the same months in 2019.

Key Findings

  • Declines in administration of recommended adolescent and adult vaccines persisted across all markets from September to November 2020; total non-influenza vaccine claims submissions were between 13–35% (adolescents) and 17–40% (adults) lower than the same period in 2019, suggesting that many individuals who should have received recommended vaccines in 2020 did not.
  • Influenza vaccination claims from August to September of the 2020–2021 season exceeded the same months of the 2019–2020 season, suggesting early heightened awareness of respiratory disease in 2020; however, those surges leveled off by October, leaving total claims through November lower than the previous season.
  • In calculating the difference between national estimates of 2020 vaccine doses and 2019 doses, Avalere found adolescents and adults in the markets studied potentially missed an estimated 26 million doses of recommended vaccines from January to November 2020 when compared to vaccination levels over the same period in 2019.

Adolescent and Adult Vaccine Claims Continued to Remain Well Below 2019 Levels

Across both adolescent and adult populations, total administration and product claims for non-influenza vaccines remained below 2019 levels through November 2020. Adolescent vaccine claims in 2020 began to increase at variable rates across all markets starting in June and again in September, when claims were 6% and 31% lower than 2019 in the Managed Medicaid and Commercial markets, respectively. While some gradual increases were observed in these markets, the overall trend continued to stagnate over the fall months and total claims in the September–November 2020 time period remained 13–35% lower compared to 2019.

Several factors may have contributed to the increases observed, such as ongoing local, state, federal, and non-governmental campaigns and efforts to ensure continuity of vaccine initiation and series completion as required for school entry. Influenza vaccine campaigns that began earlier and with greater urgency may have also contributed by providing an opportunity to engage individuals on catch-up for recommended vaccines.

Claims for adult vaccinations in 2020 compared to 2019 followed similar trends to adolescent vaccine claims across all markets analyzed. Adult vaccine claims in 2020 began to increase at variable rates across all markets starting in June but remained between 17–40% lower in the September–November 2020 time period total compared to 2019. Adult vaccine claims in the commercial market lagged furthest behind 2019 levels for much of 2020. As with the previous analysis, claims submissions did not directly correlate with changes in numbers of COVID-19 cases.

Figure 1. Aggregate Changes in Claims for All ACIP-Recommended Adolescent and Adult Vaccines* Across Markets, January–November 2019 vs. January–November 2020
Figure 1. Aggregate Changes in Claims for All ACIP-Recommended Adolescent and Adult Vaccines* Across Markets, January–November 2019 vs. January–November 2020

*Influenza vaccines are excluded from aggregate counts due to seasonality.

Early Gains Observed in Influenza Vaccination Claims Lagged as the Season Progressed

Due to seasonality of the influenza virus, Avalere analyzed influenza vaccine claim submissions separately from other vaccines. In the 2020–2021 season, influenza vaccine claims submission trends indicate that more individuals were vaccinated against influenza earlier in the 2020–2021 season than in the 2019–2020 season. In August 2020, influenza claims submissions exceeded those of August 2019 in both adolescents and adults across nearly all markets; claims were 12% lower among Managed Medicaid adults and reached as much as 55% higher for adults in Medicare Advantage plans. The early surges, however, leveled off and fell back below 2019 claims levels in October and November. Total submissions for August–November of the 2020–2021 season remained 14–35% lower than the same months in the 2019–2020 season.

Figure 2. Aggregate Changes in Claims for Influenza Vaccines Across Markets, January–November 2019 vs. January–November 2020
Figure 2. Aggregate Changes in Claims for Influenza Vaccines Across Markets, January–November 2019 vs. January–November 2020

Adolescents and Adults Missed Over 26 Million Doses of Recommended Vaccines in 2020 vs. 2019

Avalere used national enrollment data to extrapolate the difference between observed 2019 and 2020 vaccine claims to estimate the potential number of “missed doses” in 2020 on a national level. Here, “missed doses” refers to the decrease in doses of recommended adolescent and adult vaccines from 2019 to 2020.

Avalere analysis found that adolescents received an estimated 29 million doses of recommended vaccines in 2019 compared to 20.2 million doses in 2020; the difference of 8.8 million represents the number of potentially missed doses of these recommended adolescent vaccinations in 2020 (Figure 2). For adults, Avalere found that an estimated 89.4 million doses of recommended adult vaccines were administered in 2019 compared to 72.2 million doses in 2020, indicating a gap of approximately 17.2 million potentially missed doses of recommended adult vaccines in 2020.

Commercial enrollees (both adults and adolescents) had the largest volume of missed doses between 2019 and 2020. Managed Medicaid enrollees had more missed doses than Medicare (Part B FFS and Medicare Advantage), but both were notably lower than in the commercial market.

Overall, aggregate missed adolescent and adult vaccine doses demonstrate a significant gap created as a result of COVID-19 and ongoing national, state, and local restrictions and public health measures. This analysis further underscores the month-to-month compounding effect of missed recommended vaccinations, even in light of some positive trends observed in 2020.

Figure 3. Estimated Missed Doses for All Vaccine Claims Across Markets, January–November 2019 vs. January–November 2020
Figure 3. Estimated Missed Doses for All Vaccine Claims Across Markets, January–November 2019 vs. January–November 2020


The sustained lowered vaccination levels throughout much of 2020 when compared to 2019 suggest that many individuals who should have received recommended vaccines in 2020 did not. In 2020, claims for recommended adolescent and adult vaccinations have made some incremental improvements after the steeper declines at the onset of the pandemic. However, these improvements leveled off and stagnated through the fall as lockdowns and the pandemic persisted. Missed vaccine doses have accumulated throughout the pandemic, while utilization remains well below 2019 levels. As such, this vaccination deficit is likely to continue to grow, particularly as the US saw a significant rise of COVID-19 cases after November 2020.

Notably, the ACIP released a recommendation statement on May 12 allowing coadministration of COVID-19 vaccines with other vaccinations, updating an earlier Centers for Disease Control and Prevention guidance recommending a 14-day waiting period between COVID-19 vaccines and other vaccines. While ACIP’s statement cites lack of data regarding increased reactogenicity due to coadministration, it presents opportunities to renew focus on closing gaps in routine immunizations. As COVID-19 vaccine uptake continues to rise, states and the federal government may consider expanding emphasis on routine immunization programs and outreach aimed at returning to pre-pandemic vaccine uptake levels, particularly as re-opening efforts accelerate.


Updated Analysis

Avalere analyzed changes in administration of ACIP-recommended adult (≥19 years of age) and adolescent (7–18 years of age) vaccines using pre-adjudicated medical benefit Medicare FFS claims from a provider clearinghouse dataset maintained by Inovalon, Avalere’s parent company, as well as from the Inovalon MORE2 Registry®, a large scale, real-world multi-payer dataset consisting of medical, pharmacy, and lab claims and clinical data on more than 332 million de-identified patients. The provider clearinghouse dataset contains Medicare FFS Parts A and B data. The MORE2 Registry® contains claims across commercial markets (group, individual, and exchanges), Medicaid managed care, and Medicare Advantage.

Specifically, Avalere compared billing for vaccine products and administration codes—defined by Current Procedural Terminology (CPT) and Healthcare Common Procedure Coding System (HCPCS) codes—from 2019 to 2020 to identify the potential impact of the COVID-19 pandemic on vaccine administration. The claims comparison was calculated as the percentage change between years. Avalere adjusted the analysis to account for any changes in claim sources within the data by employing a “same store” analysis that requires the same providers and health plans to have submitted claims in 2019 and 2020 to ensure that reported vaccine utilization changes are not driven by the addition or subtraction of claim sources over time.

Missed Doses

Avalere used a market-specific, rate-based method to extrapolate the number of vaccine claims to a national population. Vaccines were identified using CPT and HCPCS codes for vaccine products, general vaccine administration HCPCS when product codes were not available, or National Drug Codes when neither product nor administrative codes were included on a claim. As with the refresh, a “same store” method was used across datasets. In addition to vaccine claims, the vaccination rate was based on the number of unique enrollees in each dataset, by market and age group, for each month of 2019 and 2020.

A market-specific, claims-based vaccination rate was calculated as the sum of all the vaccine claims for each month of the year divided by the number of unique enrollees in the MORE2 Registry® and provider clearinghouse data sets by market. The annual vaccination rate was then applied to 2019 national population estimates in each insurance market as reported in the American Community Survey (ACS) from the US Census Bureau.1 The 2019 claims-based vaccination rate applied to the national sample was considered the baseline for vaccination volumes, and missed doses were estimated as a difference between the baseline and the 2020 claims-based rate applied to the 2020 national population estimates.


The vaccine utilization analysis used 2 different data sources, reflecting different claim types and different sample sizes across payer markets. For Medicare FFS, Avalere leveraged a provider clearinghouse dataset that captures pre-adjudicated claims submitted by institutional and noninstitutional providers for payment and represents 5–7% of Medicare FFS claims volume nationally. Not all the submitted claims volume result in full adjudication and reimbursement from Medicare FFS. The provider clearinghouse is limited to claims submitted through Medicare Part A (inpatient and hospital coverage) and Part B (outpatient/medical coverage) and does not include Part D (drug coverage). Claims for nearly all vaccines covered in this analysis are observed in the Medicare Part B data. While Part D claims are not included in this analysis of FFS Medicare claims, some claims for Part D vaccines that were administered in the provider setting may have been captured.

For all other markets, Avalere used the Inovalon MORE2 Registry®, which includes roughly a 42% sample of the national commercially insured population, a 69% sample of the national Medicaid managed care population, and a 25% sample of the national Medicare Advantage population. Due to variability across states in billing requirements for vaccines provided through the Vaccines for Children program, this analysis may not fully capture adolescent vaccine utilization in the Managed Medicaid market.

While both data sources are nationally representative, there are likely different geographies reflected in the analysis of each market. Further, Avalere did not control for the cross-payer population shifts between 2019 and 2020 due to the insurance coverage changes. While payers captured in the analysis were the same between 2019 and 2020, changes in the vaccine utilization may be driven by underlying volume of patients enrolled in a given plan/program, in addition to access and clinical practice patterns.

Definitive vaccine administration cannot be observed within claims data because it would require long-term longitudinal data over the full range of years for which the vaccine is recommended. However, this analysis uses year-over-year comparisons to estimate the impact of COVID-19 based on the volume of claims submitted by payers over 2 years.

Vaccines Included in the Analysis

  • Influenza
  • Haemophilus influenzae (Hib)
  • Hepatitis A
  • Hepatitis B
  • Human Papillomavirus (HPV)
  • Meningococcal ACWY
  • Meningococcal B
  • Measles, Mumps, and Rubella (MMR)
  • Pneumococcal
  • Tetanus, Diphtheria, and Pertussis (Tdap)
  • Varicella Zoster (Chickenpox)
  • Herpes Zoster (Shingles)

Funding for this research was provided by GlaxoSmithKline. Avalere Health retained full editorial control.

To receive Avalere updates, connect with us.


  1. 2020 population estimates from the ACS will be available in September 2021. In this analysis, the 2020 estimates are the 2019 estimates inflated by 0.5% following 2018 to 2019 population trends cited by the US Census.

Avalere Health is an Inovalon company, a leading provider of cloud-based platforms empowering data-driven healthcare. We believe in the power of data, informing actionable insights, delivering meaningful impact, and driving stronger patient outcomes and business economics.

From beginning to end, our team synergy
produces measurable results. Let's work together.

Sign up to receive more insights about Vaccines / Preventive Services
Please enter your email address to be notified when new Vaccines / Preventive Services insights are published.

Back To Top