Real-world uptake of COVID-19 vaccination among individuals expressing vaccine hesitancy: A registry-linkage study.

INTRODUCTION: Uptake of COVID-19 vaccination remains suboptimal in the United States and other settings. Though early reports indicated that a strong majority of people were interested in receiving the COVID-19 vaccine, the association between vaccine intention and uptake is not yet fully understood. Ourobjective was todescribe predictors of vaccine uptake, and estimate the sensitivity, specificity, and predictive values of self-reported COVID-19 vaccine status compared to a comprehensive statewide COVID-19 vaccine registry. METHODS: A cohort of California residents that received a molecular test for SARS-CoV-2 infection during 24 February-5 December 2021 were enrolled in a telephone-administered survey. Survey participants were matched with records in a statewide immunization registry. Cox proportional hazards model were used to compare time to vaccination among those unvaccinated at survey enrollment by self-reported COVID-19 vaccination intention. RESULTS: Among 864 participants who were unvaccinated at the time of interview, 272 (31%) had documentation of receipt of COVID-19 vaccination at a later date; including 194/423 (45.9%) who had initially reported being willing to receive vaccination, 41/185 (22.2%) who reported being unsure about vaccination, and 37/278 (13.3%) who reported unwillingness to receive vaccination.Adjusted hazard ratios (aHRs) for registry-confirmed COVID-19 vaccination were 0.49 (95% confidence interval: 0.32-0.76) and 0.21 (0.12-0.36) for participants expressing uncertainty and unwillingness to receive vaccination, respectively, as compared with participants who reported being willing to receive vaccination. Time to vaccination was shorter among participants from higher-income households (aHR = 3.30 [2.02-5.39]) and who reported co-morbidities or immunocompromising conditions (aHR = 1.54 [1.01-2.36]).Sensitivity of self-reported COVID-19 vaccination status was 82% (80-85%) overall, and 98% (97-99%) among those referencing vaccination records; specificity was 87% (86-89%). CONCLUSION: Willingness to receive COVID-19 vaccination was an imperfect predictor of real-world vaccine uptake. Improved messaging about COVID-19 vaccination regardless of previous SARS-CoV-2 infection status may help improve uptake.

Monitoring the COVID-19 immunisation programme through a national immunisation Management system - England's experience.

BACKGROUND: In England routine vaccinations are recorded in either the patients General Practice record or in series of sub-national vaccine registers that are not interoperable. During the COVID-19 pandemic it was established that COVID vaccines would need to be delivered in multiple settings where current vaccine registers do not exist. We describe how a national vaccine register was created to collect data on COVID-19 vaccines. METHODS: The National Immunisation Management System (NIMS) was developed by a range of health and digital government agencies. Vaccinations delivered are entered on an application which is verified by individual National Health Service number in a centralised system. UKHSA receive a feed of this data to use for monitoring vaccine coverage, effectiveness, and safety. To validate the vaccination data, we compared vaccine records to self-reported vaccination dose, manufacturer, and vaccination date from the enhanced surveillance system from 11 February 2021 to 24 August 2021. RESULTS: With the Implementation of NIMS, we have been able to successfully record COVID-19 vaccinations delivered in multiple settings. Of 1,129 individuals, 97.8% were recorded in NIMS as unvaccinated compared to those who self-reported as unvaccinated. One hundred percent and 99.3% of individuals recorded in NIMS as having at least one dose and two doses of the COVID-19 vaccine were also self-reported as having at least one and two doses, respectively. Of the 100% reporting at least one dose, 98.3% self-reported the same vaccination date as NIMS. A total of 98.8% and 99.3% had the same manufacturer information for their first dose and second dose as that which was self-reported, respectively. DISCUSSION: Daily access to individual-level vaccine data from NIMS has allowed UKHSA to estimate vaccine coverage and provide some of the world's first vaccine effectiveness estimates rapidly and accurately.

Agreement between state registry, health record, and self-report of influenza vaccination.

BACKGROUND: Documentation of influenza vaccination, including the specific product received, is critical to estimate annual vaccine effectiveness (VE). METHODS: We assessed performance of the Michigan Care Improvement Registry (MCIR) in defining influenza vaccination status relative to documentation by provider records or self-report among subjects enrolled in a study of influenza VE from 2011 through 2019. RESULTS: The specificity and positive predictive value of MCIR were high; however, >10% of vaccinations were identified only by other sources each season. The proportion of records captured by MCIR increased from a low of 67% in 2013-2014 to a high of 89% in 2018-2019, largely driven by increased capture of vaccination among adults. CONCLUSIONS: State vaccine registries, such as MCIR, are important tools for documenting influenza vaccination, including the specific product received. However, incomplete capture suggests that documentation from other sources and self-report should be used in combination with registries to reduce misclassification.

Challenges with hepatitis B vaccination of high risk adults - A pilot program.

BACKGROUND: Acute hepatitis B virus (HBV) infections in the United States occur predominantly among persons aged 30-59 years. The Centers for Disease Control and Prevention (CDC) recommends vaccination of adults at increased risk for HBV infection. Completing the hepatitis B (HepB) vaccine dose-series is critical for optimal immune response. OBJECTIVES: CDC funded 14 health departments (awardees) from 2012 to 2015 to implement a pilot HepB vaccination program for high-risk adults. We evaluated the pilot program to assess vaccine utilization; vaccine dose-series completion, including by vaccination location type; and implementation challenges. METHODS: Awardees collaborated with sites providing health care to persons at increased risk for HBV infection. Awardees collected information on doses administered, vaccine dose-series completion, and challenges completing and tracking vaccinations, including use of immunization information systems (IIS). Data were reported by each awardee in aggregate to CDC. RESULTS: Six of 14 awardees administered 47,911 doses and were able to report patient-level dose-series completion. Among persons who received dose 1, 40.4% received dose 2, and 22.3% received dose 3. Local health department clinics had the highest 3-dose-series completion, 60.6% (531/876), followed by federally qualified health centers at 38.0% (923/2432). While sexually transmitted diseases (STD) clinics administered the most doses in total (17,173 [35.8% of 47,911 doses]), 3-dose-series completion was low (17.1%). The 14 awardees reported challenges regarding completing and tracking dose-series, including reaching high-risk adults for follow-up and inconsistencies in use of IIS or other tracking systems across sites. CONCLUSIONS: Dose-series completion was low in all settings, but lowest where patients may be less likely to return for follow-up (e.g., STD clinics). Routinely assessing HepB vaccination needs of high-risk adults, including through use of IIS where available, may facilitate HepB vaccine dose-series completion.

Coverage and timeliness of vaccination and the validity of routine estimates: Insights from a vaccine registry in Kenya.

BACKGROUND: The benefits of childhood vaccines are critically dependent on vaccination coverage. We used a vaccine registry (as gold standard) in Kenya to quantify errors in routine coverage methods (surveys and administrative reports), to estimate the magnitude of survivor bias, contrast coverage with timeliness and use both measures to estimate population immunity. METHODS: Vaccination records of children in the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya were combined with births, deaths, migration and residence data from 2010 to 17. Using inverse survival curves, we estimated up-to-date and age-appropriate vaccination coverage, calculated mean vaccination coverage in infancy as the area under the inverse survival curves, and estimated the proportion of fully immunised children (FIC). Results were compared with published coverage estimates. Risk factors for vaccination were assessed using Cox regression models. RESULTS: We analysed data for 49,090 infants and 48,025 children aged 12-23 months in 6 birth cohorts and 6 cross-sectional surveys respectively, and found 2nd year of life surveys overestimated coverage by 2% compared to birth cohorts. Compared to mean coverage in infants, static coverage at 12 months was exaggerated by 7-8% for third doses of oral polio, pentavalent (Penta3) and pneumococcal conjugate vaccines, and by 24% for the measles vaccine. Surveys and administrative coverage also underestimated the proportion of the fully immunised child by 10-14%. For BCG, Penta3 and measles, timeliness was 23-44% higher in children born in a health facility but 20-37% lower in those who first attended during vaccine stock outs. CONCLUSIONS: Standard coverage surveys in 12-23 month old children overestimate protection by ignoring timeliness, and survivor and recall biases. Where delayed vaccination is common, up-to-date coverage will give biased estimates of population immunity. Surveys and administrative methods also underestimate FIC prevalence. Better measurement of coverage and more sophisticated analyses are required to control vaccine preventable diseases.

Vacuna de Hepatitis B: Productos registrados en Argentina y métodos generales de valoración de potencia / Hepatitis b vaccine: registered products in argentina and general methods for potency assessment

La infección de hepatitis B, causada por el virus de nombre homónimo, es una de las infecciones virales más graves. Este virus infecta a más de 500 millones de personas en el mundo siendo la causa más frecuente de hepatitis crónica, cirrosis y carcinoma hepatocelular. A pesar de los esfuerzos orientados al desarrollo de terapias eficientes, actualmente no existe un tratamiento específico para esta enfermedad, por lo que constituye un problema de salud a nivel mundial. Por este motivo, la Dirección de Evaluación y Control de Biológicos y Radiofármacos realizó una revisión bibliográfica acerca de los productos comercializados de la vacuna en nuestro país y los ensayos de control de calidad.

Hepatitis B infection, caused by its namesake virus, is one of the most serious viral infections. This virus affects more than 500 million people in the world which is the most frequent cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma. Despite efforts aimed at the development of efficient therapies, there is currently no specific treatment for this disease, which is an important global health problem. For this reason, the Directorate of Evaluation and Control of Biologics and Radiopharmaceuticals carried out a literature review about commercialized hepatitis B vaccines in our country and its quality control assays.

Investigation and management of a large community mumps outbreak among young adults in Toronto, Canada, January 2017-February 2018.

BACKGROUND: In 2017, a mumps outbreak was identified in a cohort of 18-34 year olds in Toronto, Canada. OBJECTIVE: To describe a large community mumps outbreak in an urban centre from January 2017 to February 2018 among young adults. METHODS: A broad range of interventions were implemented in an attempt to reach the target audience; including case and contact management, vaccination clinics at schools and clinicians' offices, school exclusions, bar inspections, traditional communication strategies (including health care provider updates and posters) and newer communication strategies (including three sequential social media campaigns). RESULTS: A total of 143 cases of mumps were identified. Although cases' ages ranged from three to 72 years, most (76%) were 18-34 year olds, many of whom had frequented bars and local food establishments in downtown Toronto. 84% (n=120) of the cases were community-acquired. Only 16% (n=23) of the cases reported exposures in schools and post-secondary school institutions. Of those, 39% (n=56) of cases had an unknown vaccination history; 34% (n=49) were either not vaccinated or partially vaccinated with one dose of measles-mumps-rubella vaccine; and 27% (n=38) had received the recommended two doses of mumps vaccine. Determining vaccination status was a challenge, in part due to the lack of a registry. Vaccination was recommended when subjects were known to have had fewer than two doses of vaccine or had an unknown vaccination status. A social media campaign, emphasizing the risk of social activities if not protected from the mumps, yielded over 500,000 impressions from Facebook and Twitter messages and ads and an impressive engagement rate of between 1% and 10x%. CONCLUSION: This was the largest mumps outbreak in Toronto in over 20 years. Among young adults, ongoing social media and traditional communication campaigns can contribute to the control of community mumps outbreaks. Encouraging vaccine uptake is desirable, but without a vaccine registry it is difficult to assess vaccination coverage among adults. Susceptible cohorts of young adults who were not adequately vaccinated pose a risk for future outbreaks. Given that almost 30% of the mumps cases were fully vaccinated with two doses of mumps-containing vaccine, even two doses may not provide complete protection.