Medication Safety: Analysis Shows PPSV23 Is Not Associated With Higher Risk of Serious Outcomes

Updated safety evidence for the 23-valent pneumococcal polysaccharide vaccine (PPSV23) demonstrates that it is not associated with a higher risk of serious systemic adverse events (AEs), according to results of an analysis published in JAMA Network Open. Although the vaccine has been widely used, there have been safety concerns due to outdated evidence, according to the study authors.¹

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The Advisory Committee on Immunization Practices recommends that all older adults receive 1 dose of PPSV23. The vaccine has more than 3 decades of safety evidence and clinical experience, and most AEs are mild in nature and resolve within a few days, according to the authors.¹

Despite these data, uptake of pneumococcal vaccines has been low in eligible older populations, even in high-income countries with routine and universal vaccination programs. Data from an American study of Medicare claims from 2013 to 2015 showed that most participants did not receive a pneumococcal vaccine within the first year of turning 65 years.²

Reasons for the lagging uptake vary, but they include distrust of the health system, lack of health literacy, and administrative barriers. Researchers stressed that obstacles can be particularly difficult for marginalized communities, necessitating continued efforts to serve these populations.²

In the new study of PPSV23 AEs, the investigators aimed to assess any potential association between cardiovascular, neurological, and immunological AEs and PPSV23 in older adults to better address any possible limitations regarding uptake.¹

Investigators linked data from the Korea Immunization Registry Information System between July 2018 and July 2022 to the National Health Information Database. The data included 18 different types of vaccines, demographics, and clinical information from the South Korean patient population. With that information, investigators then used national codes to find the exposure and outcome data, according to the study authors.¹

Individuals 65 years or older who had received PPSV23 were included in the study, and investigators included 4355 individuals who experienced AEs. The population had a mean age of 72.4 years, were 52.1% male, and had a higher proportion of comorbidities than those who did not have an AE but were vaccinated.¹

The investigators assessed for 6 cardiovascular outcomes, 2 neurological outcomes, and 3 immunological outcomes. These included myocardial infarction, atrial fibrillation, cardiomyopathy, heart failure, hypotension, myocarditis or pericarditis, stroke, Bell palsy, Guillain-Barré syndrome, sepsis, thrombocytopenia, and anaphylaxis. Individuals who had a history of any of these diagnoses within 1 year before cohort entry were excluded from the study.¹

In the self-controlled risk interval analysis, investigators found no increased risk of cardiovascular, neurological, or immunological events following vaccination. They found null risks for all cardiovascular events except cardiomyopathy, which had a significantly lower risk interval compared with other cardiovascular events. Bell palsy and Guillain-Barré syndrome were not associated with vaccination, and vaccination did not increase the risk of sepsis, thrombocytopenia, or anaphylaxis, the study authors said.¹

Additionally, none of the subgroups showed positive associations between PPSV23 or any of the 3 event categories. Although the results were not significant, investigators did note that participants with a history of cardiovascular disease tended to have an increased risk for cardiovascular events.¹

The study authors concluded that PPSV23 was most likely associated with a higher risk of immunological events for those who were immunocompromised, but the number of events was low. They noted limitations of the study, including the fact that AEs could have been underestimated because only individuals who had received 1 dose of the vaccine were included in the study. Anyone who had received more than 1 dose was excluded.¹

Educating patients about data such as these can make a key difference in vaccine uptake, and pharmacists are well positioned to provide that information. Additionally, research findings have suggested that informational campaigns specifically targeted at certain audiences (ie, older adults), prioritization of vaccination schemes, and taking advantage of regular interactions with patients can all make significant differences.²

References

1. Yoon D, Jeon HL, Kim JH, Lee H, Shin JY. Cardiovascular, neurological, and immunological adverse events and the 23-valent pneumococcal polysaccharide vaccine. JAMA Netw Open. 2024;7(1):e2352597. doi:10.1001/jamanetworkopen.2023.52597

2. Kirubarajan A, Lynch M, Nasreen S, et al. Increasing pneumococcal vaccine uptake in older adults: a scoping review of interactions in high-income countries. BMC Geriatr. 2023;23(1):2. doi:10.1186/s12877-022-03653-9