Invasive Pneumococcal Disease and Potential Impact of Pneumococcal Conjugate Vaccines Among Adults, Including Persons Experiencing Homelessness-Alaska, 2011-2020

BACKGROUND

Adults aged ≥65 years, adults with certain underlying medical conditions, and persons experiencing homelessness are at increased risk for invasive pneumococcal disease (IPD). Two new pneumococcal conjugate vaccines, 15-valent pneumococcal conjugate vaccine (PCV15) and 20-valent pneumococcal conjugate vaccine (PCV20), were recently approved for use in US adults. We describe the epidemiology of IPD among Alaska adults and estimate the proportion of IPD cases potentially preventable by new vaccines.

METHODS

We used statewide, laboratory-based surveillance data to calculate and compare IPD incidence rates and 95% confidence intervals (CIs) among Alaska adults aged ≥18 years during 2011-2020 and estimate the proportion of IPD cases that were caused by serotypes in PCV15 and PCV20.

RESULTS

During 2011-2020, 1164 IPD cases were reported among Alaska adults for an average annual incidence of 21.3 cases per 100 000 adults per year (95% CI, 20.1-22.5). Incidence increased significantly during the study period (P < .01). IPD incidence among Alaska Native adults was 4.7 times higher than among non-Alaska Native adults (95% CI, 4.2-5.2). Among adults experiencing homelessness in Anchorage, IPD incidence was 72 times higher than in the general adult population (95% CI, 59-89). Overall, 1032 (89%) Alaska adults with IPD had an indication for pneumococcal vaccine according to updated vaccination guidelines; 456 (39%) and 700 (60%) cases were caused by serotypes in PCV15 and PCV20, respectively.

CONCLUSIONS

Use of PCV15 and PCV20 could substantially reduce IPD among adults in Alaska, including Alaska Native adults and adults experiencing homelessness.

Temporally Associated Invasive Pneumococcal Disease and SARS-CoV-2 Infection, Alaska, USA, 2020-2021

Streptococcus pneumoniae can co-infect persons who have viral respiratory tract infections. However, research on S. pneumoniae infections that are temporally associated with SARS-CoV-2 infections is limited. We described the epidemiology and clinical course of patients who had invasive pneumococcal disease (IPD) and temporally associated SARS-CoV-2 infections in Alaska, USA, during January 1, 2020-December 23, 2021. Of 271 patients who had laboratory-confirmed IPD, 55 (20%) had a positive SARS-CoV-2 test result. We observed no major differences in age, race, sex, or underlying medical conditions among IPD patients with and without SARS-CoV-2. However, a larger proportion of IPD patients with SARS-CoV-2 died (16%, n = 9) than for those with IPD alone (4%, n = 9) (p<0.01). IPD patients with SARS-CoV-2 were also more likely to be experiencing homelessness (adjusted OR 3.5; 95% CI 1.7-7.5). Our study highlights the risk for dual infection and ongoing benefits of pneumococcal and COVID-19 vaccination, especially among vulnerable populations.

Invasive Group B Streptococcal Disease Among Non-Pregnant Adults - Alaska, 2004-2023

We describe the epidemiology of invasive group B streptococcal (GBS) disease among non-pregnant Alaska adults using statewide surveillance data. During 2004-2023, 880 cases of invasive GBS disease were reported for an age-adjusted annual incidence of 9.1 (95% CI, 8.5-9.7) cases per 100,000 adults. Incidence increased 1.9-fold (95% CI, 1.6-2.2) between 2004-2013 and 2014-2023. Adults aged ≥65 years had a 4.4-fold higher risk of invasive disease compared to younger adults, and 47% of adults with invasive GBS had diabetes. Healthcare providers should be aware of populations at increased risk, potentially allowing for more prompt treatment.

Occupational and environmental exposures among Alaska Native and American Indian people living in Alaska and the Southwest United States

Most occupational and environmental research describes associations between specific occupational and environmental hazards and health outcomes, with little information available on population-level exposure, especially among unique subpopulations. The authors describe the prevalence of self-reported lifetime exposure to nine occupational and environmental hazards among 11,326 American Indian and Alaska Native (AI/AN) adults enrolled in the Education and Research Towards Health (EARTH) Study in the Southwest U.S. and Alaska. The top three hazards experienced by AI/AN people in Alaska were petroleum products, military chemicals, and asbestos. The top three hazards experienced by AI/AN living in the Southwest U.S. were pesticides, petroleum, and welding/silversmithing. The study described here found that male sex, lower educational attainment, AI/AN language use, and living in the Southwest U.S. (vs. Alaska) were all associated with an increased likelihood of hazard exposure. The authors' study provides baseline data to facilitate future exposure-response analyses. Future studies should measure dose and duration as well as environmental hazards that occur in community settings.