Factors Associated with Delayed or Missed Second-Dose mRNA COVID-19 Vaccination among Persons >12 Years of Age, United States

Variation in the time to complete the primary COVID-19 vaccine series by race, ethnicity, and geography among older US adults

INTRODUCTION

Racial and ethnic disparities in COVID-19 vaccine access are well-documented; however, few studies have examined whether racial disparities are modified by other factors, including geographic location and area-level deprivation.

METHODS

We conducted an observational study using the COVVAXAGE database. Medicare beneficiaries who received the COVID-19 vaccine primary series (two doses) between 01/01/2021 and 12/31/2021 were included. Racial differences in the time between doses was assessed by urbanicity using g-formula methods.

RESULTS

We identified 11,924,990 beneficiaries (mean age = 75.4; 60 % female; 80 % White). Most beneficiaries (97.1 %) received their second vaccine on time. Delayed second doses were more common among beneficiaries who were Black (RRdelayed = 1.30, 95 %CI = 1.28-1.31) and rural (RRdelayed = 1.27, 95 %CI = 1.25-1.29) relative to White and urban beneficiaries. Racial disparities in delayed vaccinations varied in magnitude by degree of urbanicity.

CONCLUSIONS

Most beneficiaries received their second COVID-19 vaccine on time. Racial disparities were observed and shown to vary by geographic area.

Social and demographic factors associated with receipt of a COVID-19 vaccine initial booster dose and with interval between primary series completion and initial booster dose uptake among persons aged ≥ 12 years, United States, August 2021-October 2022

COVID-19 booster dose vaccination has been crucial in ensuring protection against COVID-19 including recently predominant Omicron variants. Because vaccines against newer SARS-CoV- 2 variants are likely to be recommended in future, it will be valuable to understand past booster dose uptake among different demographic groups. Using U.S. vaccination data, this study examined intervals between primary series completion and receipt of first booster dose (monovalent or bivalent) during August 2021 - October 2022 among persons ≥12 years of age who had completed a COVID-19 vaccine primary series by October 2021. Sub-populations who were late booster recipients (received a booster dose ≥12 months after the primary series) or received no booster dose included persons <35 years old, Johnson & Johnson/Janssen vaccine primary dose recipients, persons in certain racial and ethnic groups, and persons living in rural and more socially vulnerable areas, and in the South region of the United States; these groups may benefit the most from public health outreach efforts to achieve timely COVID-19 vaccination completion in future.

Timely Second-Dose Completion of mRNA COVID-19 Vaccination at Community-Based and Mobile Vaccine Clinics in Maryland

To assess factors associated with timely second-dose completion, we analyzed COVID-19 vaccine data from community-based and mobile vaccine clinics in Maryland. Overall, 85.3% of patients received a timely second dose. Factors associated with a timely second dose included Latino ethnicity (adjusted odds ratio [AOR] = 1.5; 95% confidence interval [CI] = 1.1, 2.0) and receipt of the first dose at community-based vaccine clinics (AOR = 2.1; 95% CI = 1.8, 2.5). Future health initiatives for underserved communities should focus on establishing vaccine clinics in trusted community spaces with culturally sensitive support. (Am J Public Health. 2023;113(9):947-951. https://doi.org/10.2105/AJPH.2023.307338).

Modeling Behavior and Vaccine Hesitancy Using Twitter-Derived US Population Sentiment during the COVID-19 Pandemic to Predict Daily Vaccination Inoculations

The sentiment analysis of social media for predicting behavior during a pandemic is seminal in nature. As an applied contribution, we present sentiment-based regression models for predicting the United States COVID-19 first dose, second dose, and booster daily inoculations from 1 June 2021 to 31 March 2022. The models merge independent variables representing fear of the virus and vaccine hesitancy. Large correlations exceeding 77% and 84% for the first-dose and booster-dose models inspire confidence in the merger of the independent variables. Death count as a traditional measure of fear is a lagging indicator of inoculations, while Twitter-positive and -negative tweets are strong predictors of inoculations. Thus, the use of sentiment analysis for predicting inoculations is strongly supported with administrative events being catalysts for tweets. Non-inclusion in the second-dose regression model of data occurring before the 1 June 2021 timeframe appear to limit the second-dose model results-only achieving a moderate correlation exceeding 53%. Limiting tweet collection to geolocated tweets does not encompass the entire US Twitter population. Nonetheless, results from Kaiser Family Foundation (KFF) surveys appear to generally support the regression factors common to the first-dose and booster-dose regression models and their results.