COVID-19 has been associated with an increased risk for thromboembolic events, including ischemic stroke, venous thromboembolism, and myocardial infarction. Studies have reported lower rates of COVID-19-related thromboembolic events among persons who received the COVID-19 vaccine compared with persons who did not, but rigorous estimates of vaccine effectiveness (VE) in preventing COVID-19-related thromboembolic events are lacking. This analysis estimated the incremental benefit of receipt of a bivalent mRNA COVID-19 vaccine after receiving an original monovalent COVID-19 vaccine. To estimate VE of a bivalent mRNA COVID-19 dose in preventing thromboembolic events compared with original monovalent COVID-19 vaccine doses only, two retrospective cohort studies were conducted among Medicare fee-for-service enrollees during September 4, 2022-March 4, 2023. Effectiveness of a bivalent COVID-19 vaccine dose against COVID-19-related thromboembolic events compared with that of original vaccine alone was 47% (95% CI = 45%-49%) among Medicare enrollees aged ≥65 years and 51% (95% CI = 39%-60%) among adults aged ≥18 years with end stage renal disease receiving dialysis. VE was similar among Medicare beneficiaries with immunocompromise: 46% (95% CI = 42%-49%) among adults aged ≥65 years and 45% (95% CI = 24%-60%) among those aged ≥18 years with end stage renal disease. To help prevent complications of COVID-19, including thromboembolic events, adults should stay up to date with COVID-19 vaccination.

IMPORTANCE: The association of 13-valent pneumococcal conjugate vaccine (PCV13) use with pneumonia hospitalization in older adults, especially those with underlying medical conditions, is not well described. OBJECTIVE: To evaluate the association of PCV13 use with pneumonia, non-health care-associated (non-HA) pneumonia, and lobar pneumonia (LP) hospitalization among US Medicare beneficiaries 65 years or older. DESIGN, SETTING, AND PARTICIPANTS: This cohort study with time-varying exposure assignment analyzed claims data from US Medicare beneficiaries 65 years or older enrolled in Parts A/B with a residence in the 50 US states or the District of Columbia by September 1, 2014. New Medicare Parts A/B beneficiaries within 6 months after their 65th birthday were continuously included in the cohort after September 1, 2014, and followed through December 31, 2017. Participants were censored if they died, changed enrollment status, or developed a study outcome. Most of the analyses were conducted from 2018 to 2019, and additional analyses were performed from 2021 to 2022. EXPOSURES: Use of PCV13 vaccination 14 days or more before pneumonia hospitalization. MAIN OUTCOMES AND MEASURES: Discrete-time survival models were used to estimate the incidence rate ratio (IRR) and number of pneumonia hospitalizations averted through PCV13 use. The adjusted IRR for the association of PCV13 vaccination with pneumonia hospitalization was used to estimate vaccine effectiveness (VE). RESULTS: At the end of follow-up (December 2017), 24121625 beneficiaries (13593975 women [56.4%]; 418005 [1.7%] Asian, 1750807 [4.8%] Black, 338044 [1.4%] Hispanic, 111508 [0.5%] Native American, and 20700948 [85.8%] White individuals) were in the cohort; 4936185 (20.5%) had received PCV13 only, and 10646220 (79.5%) had not received any pneumococcal vaccines. More than half of the beneficiaries in the cohort were younger than 75 years, White, and had either immunocompromising or chronic medical conditions. Coverage with PCV13 increased from 0.8% (September 2014) to 41.5% (December 2017). The VE for PCV13 was estimated at 6.7% (95% CI, 5.9%-7.5%) for pneumonia, 4.7% (95% CI, 3.9%-5.6%) for non-HA pneumonia, and 5.8% (95% CI, 2.6%-8.9%) for LP. From September 2014 through December 2017, an estimated 35127 pneumonia (95% CI, 33011-37270), 24643 non-HA pneumonia (95% CI, 22761-26552), and 1294 LP (95% CI, 797-1819) hospitalizations were averted through PCV13 use. CONCLUSIONS AND RELEVANCE: The study results suggest that PCV13 use was associated with reduced pneumonia hospitalization among Medicare beneficiaries 65 years or older, many of whom had underlying medical conditions. Increased PCV13 coverage and use of recently approved higher-valent pneumococcal conjugate vaccines may avert additional pneumonia hospitalizations in adults.

IMPORTANCE: Guillain-Barré syndrome can be reported after vaccination. This study assesses the risk of Guillain-Barré syndrome after administration of recombinant zoster vaccine (RZV or Shingrix), which is administered in 2 doses 2 to 6 months apart. OBJECTIVE: Use Medicare claims data to evaluate risk of developing Guillain-Barré syndrome following vaccination with zoster vaccine. DESIGN, SETTING, AND PARTICIPANTS: This case series cohort study included 849 397 RZV-vaccinated and 1 817 099 zoster vaccine live (ZVL or Zostavax)-vaccinated beneficiaries aged 65 years or older. Self-controlled analyses included events identified from 2 113 758 eligible RZV-vaccinated beneficiaries 65 years or older. We compared the relative risk of Guillain-Barré syndrome after RZV vs ZVL, followed by claims-based and medical record-based self-controlled case series analyses to assess risk of Guillain-Barré syndrome during a postvaccination risk window (days 1-42) compared with a control window (days 43-183). In self-controlled analyses, RZV vaccinees were observed from October 1, 2017, to February 29, 2020. Patients were identified in the inpatient, outpatient procedural (including emergency department), and office settings using Medicare administrative data. EXPOSURES: Vaccination with RZV or ZVL vaccines. MAIN OUTCOMES AND MEASURES: Guillain-Barré syndrome was identified in Medicare administrative claims data, and cases were assessed through medical record review using the Brighton Collaboration case definition. RESULTS: Amongst those who received RZV vaccinees, the mean age was 74.8 years at first dose, and 58% were women, whereas among those who received the ZVL vaccine, the mean age was 74.3 years, and 60% were women. In the cohort analysis we detected an increase in risk of Guillain-Barré syndrome among RZV vaccinees compared with ZVL vaccinees (rate ratio [RR], 2.34; 95% CI, 1.01-5.41; P = .047). In the self-controlled analyses, we observed 24 and 20 cases during the risk and control period, respectively. Our claims-based analysis identified an increased risk in the risk window compared with the control window (RR, 2.84; 95% CI, 1.53-5.27; P = .001), with an attributable risk of 3 per million RZV doses (95% CI, 0.62-5.64). Our medical record-based analysis confirmed this increased risk (RR, 4.96; 95% CI, 1.43-17.27; P = .01). CONCLUSIONS AND RELEVANCE: Findings of this case series cohort study indicate a slightly increased risk of Guillain-Barré syndrome during the 42 days following RZV vaccination in the Medicare population, with approximately 3 excess Guillain-Barré syndrome cases per million vaccinations. Clinicians and patients should be aware of this risk, while considering the benefit of decreasing the risk of herpes zoster and its complications through an efficacious vaccine, as risk-benefit balance remains in favor of vaccination.

Using Medicare claims data on prescriptions of oseltamivir dispensed to people 65 years old and older, we present a descriptive analysis of patterns of influenza activity in the United States for 579 core-based statistical areas (CBSAs) from the 2010-2011 through the 2015-2016 influenza seasons. During this time, 1,010,819 beneficiaries received a prescription of oseltamivir, ranging from 45,888 in 2011-2012 to 380,745 in 2014-2015. For each season, the peak weekly number of prescriptions correlated with the total number of prescriptions (Pearson's r >/= 0.88). The variance in peak timing decreased with increasing severity (p < 0.0001). Among these 579 CBSAs, neither peak timing, nor relative timing, nor severity of influenza seasons showed evidence of spatial autocorrelation (0.02 </= Moran's I </= 0.23). After aggregating data to the state level, agreement between the seasonal severity at the CBSA level and the state level was fair (median Cohen's weighted kappa = 0.32, interquartile range = 0.26-0.39). Based on seasonal severity, relative timing, and geographic place, we used hierarchical agglomerative clustering to join CBSAs into influenza zones for each season. Seasonal maps of influenza zones showed no obvious patterns that might assist in predicting influenza zones for future seasons. Because of the large number of prescriptions, these data may be especially useful for characterizing influenza activity and geographic distribution during low severity seasons, when other data sources measuring influenza activity are likely to be sparse.

BACKGROUND: Over 34 million residents of the United States aged 65 years old and older are also Medicare prescription drug beneficiaries. Medical claims records for this age group potentially provide a wealth of data for better understanding influenza epidemiology. OBJECTIVE: The purpose of this study was to evaluate data on oseltamivir dispensing extracted from medical claims records as an indicator of influenza activity in the United States for the 2010-11 through 2014-15 influenza seasons. METHODS: We used Centers for Medicare and Medicaid Services (CMS) medical claims data to evaluate the weekly number of therapeutic oseltamivir prescriptions dispensed following a rapid influenza diagnostic test among beneficiaries 65 years old and older as an indicator of influenza timing and intensity. We compared the temporal changes in this indicator to changes in the proportion of influenza-like illnesses among outpatient visits in the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet) by administrative regions defined by the U.S. Department of Health and Human Services. Using the moving epidemic method, we determined intensity thresholds and categorized the severity of seasons for both CMS and ILINet data. RESULTS: CMS oseltamivir data and ILINet data were strongly correlated by administrative region (median Spearman's rho = 0.78, interquartile range = 0.73-0.80). CMS oseltamivir data and ILINet data substantially agreed (Cohen's weighted kappa = 0.62) as to the seasonal severity across administrative regions. CONCLUSIONS: Our results support the use of oseltamivir dispensing in medical claims data as an indicator of US influenza activity. This article is protected by copyright. All rights reserved.

Background: Statins are used to reduce cardiovascular disease risk. Recent studies suggest that statin use may be associated with an increased influenza risk among influenza vaccinees. We used Medicare data to evaluate associations between statins and risks of influenza-related encounters among vaccinees. Methods: In this retrospective cohort study, we identified Medicare beneficiaries aged >65 years who received high-dose (HD) or standard-dose (SD) influenza vaccines at pharmacies from 2010-11 through 2014-15. Statin users were matched to non-users by vaccine type, demographics, prior medical encounters, and comorbidities. We used multivariable Poisson models to estimate associations between statin use around the time of vaccination and risk of influenza-related encounters. Study outcomes included influenza-related office visits with a rapid test followed by dispensing of oseltamivir, and influenza-related hospitalizations (including emergency room visits), during high influenza circulation periods. Results: The study included 1,403,651 statin users matched to non-users. Cohorts were well-balanced, with standardized mean differences </=0.03 for all measured covariates. For statin users, compared to non-users, the adjusted relative risk was 1.086 (95% confidence interval [CI] 1.025-1.150) for influenza-related visits and 1.096 (95% CI 1.013-1.185) for influenza-related hospitalizations. The risk difference ranged from -0.02 to 0.23 for influenza-related visits and from -0.04 to 0.13 for hospitalizations, depending on season severity. Results were similar for HD and SD vaccinees, and for non-synthetic and synthetic statin users. Conclusions: Among 2.8 million Medicare beneficiaries, these results suggest that statin use around time of vaccination does not substantially affect the risk of influenza-related medical encounters among older adults.

On September 19, 2014, CDC published the Advisory Committee on Immunization Practices (ACIP) recommendation for the routine use of 13-valent pneumococcal conjugate vaccine (PCV13) among adults aged ≥65 years, to be used in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23) (1). This replaced the previous recommendation that adults aged ≥65 years should be vaccinated with a single dose of PPSV23. As a proxy for estimating PCV13 and PPSV23 vaccination coverage among adults aged ≥65 years before and after implementation of these revised recommendations, CDC analyzed claims for vaccination submitted for reimbursement to the Centers for Medicare & Medicaid Services (CMS). Claims from any time during a beneficiary's enrollment in Medicare Parts A (hospital insurance) and B (medical insurance) since reaching age 65 years were assessed among beneficiaries continuously enrolled in Medicare Parts A and B during annual periods from September 19, 2009, through September 18, 2016. By September 18, 2016, 43.2% of Medicare beneficiaries aged ≥65 years had claims for at least 1 dose of PPSV23 (regardless of PCV13 status), 31.5% had claims for at least 1 dose of PCV13 (regardless of PPSV23 status), and 18.3% had claims for at least 1 dose each of PCV13 and PPSV23. Claims for either type of pneumococcal vaccine were highest among beneficiaries who were older, white, or with chronic and immunocompromising medical conditions than among healthy adults. Implementation of the National Vaccine Advisory Committee's standards for adult immunization practice to assess vaccination status at every patient encounter, recommend needed vaccines, and administer vaccination or refer to a vaccinating provider might help increase pneumococcal vaccination coverage and reduce the risk for pneumonia and invasive pneumococcal disease among older adults (2).

BACKGROUND: Institutionalized adults are at increased risk of morbidity and mortality from influenza and pneumococcal infection. Influenza and pneumococcal vaccination have been shown to be effective in reducing hospitalization and deaths due to pneumonia and influenza in this population. OBJECTIVE: To assess trends in influenza vaccination coverage among US nursing home residents from the 2005-2006 through 2014-2015 influenza seasons and trends in pneumococcal vaccination coverage from 2006 to 2014 among US nursing home residents, by state and demographic characteristics. METHODS: Data were analyzed from the Centers for Medicare and Medicaid Services' (CMS's) Minimum Data Set (MDS). Influenza and pneumococcal vaccination status were assessed for all residents of CMS-certified nursing homes using data reported to the MDS by all certified facilities. RESULTS: Influenza vaccination coverage increased from 71.4% in the 2005-2006 influenza season to 75.7% in the 2014-2015 influenza season and pneumococcal vaccination coverage increased from 67.4% in 2006 to 78.4% in 2014. Vaccination coverage varied by state, with influenza vaccination coverage ranging from 50.0% to 89.7% in the 2014-2015 influenza season and pneumococcal vaccination coverage ranging from 55.0% to 89.7% in 2014. Non-Hispanic black and Hispanic residents had lower coverage compared with non-Hispanic white residents for both vaccines, and these differences persisted over time. CONCLUSION: Influenza and pneumococcal vaccination among US nursing home residents remains suboptimal. Nursing home staff can employ strategies such as provider reminders and standing orders to facilitate offering vaccination to all residents along with culturally appropriate vaccine promotion to increase vaccination coverage among this vulnerable population.