Eunice Veronica Zeca

Background: Mozambique introduced the 10-valent pneumococcal conjugate vaccine (PCV10) in 2013 using a three-dose primary series with no booster dose (3p+0) and later switched to the PCV13 using a schedule of two primary doses with one booster (2p+1). We aimed to describe the burden and serotype distribution of pneumococcal meningitis in children under 5 years of age in Mozambique over an eleven-year period starting with the year of PCV10 introduction, and assess the impact of the PCV vaccine and schedule changes. Methods: We analysed meningitis surveillance data in Mozambique from March 2013 through to December 2023. Cerebrospinal fluid (CSF) samples were collected from eligible children in three referral hospitals (Maputo Central Hospital [south], Beira Central Hospital [central], and Nampula Central Hospital [north]). Culture and polymerase chain reaction assay (qPCR) were performed on each sample. S. pneumoniae-positive samples were subsequently serotyped using multiplex assay. We estimated annual incidence rates for pneumococcal meningitis in children under 5 years old following the PCVs’ introduction (2013–2023). The impact of the product switch and schedule change from PCV10/3p+0 to PCV13/2p+1 on the burden and serotype distribution of pneumococcal meningitis was assessed. Results: Of the 4075 CSF samples tested, 7.4% (301/4075) were positive for S. pneumoniae, 2.5% (103/4075) for H. influenzae, and 1.0% (42/4075) for N. meningitidis. Pneumococcal meningitis incidence in children under five reduced from 44.7 cases per 100,000 in 2013 to 4.6 cases per 100,000 in 2023, an 89.7% reduction. In the PCV13/2p+1 period (2020–2023), pneumococcal meningitis incidence was 51.2% lower than the PCV10/3p+0 period (2013–2017) (IRR 0.49, 95% CI 0.4–0.6; p < 0.001). PCV10-serotype pneumococcal meningitis incidence among children under five decreased by 65.6% in the PCV13/2p+1 period (IRR 0.34, 95% CI 0.2–0.6; p < 0.001). We detected zero cases of pneumococcal meningitis due to the PCV13-serotype in 2020–2023, whereas non-PCV10/13-serotypes increased by 76% (IRR 1.76, 95% CI 1.2–2.6; p = 0.004). The case–fatality proportion decreased by 71.9% (95% CI 62.9–84.8%) in the PCV13/2p+1 period. Conclusions: Since the introduction of PCVs in Mozambique, the burden of pneumococcal meningitis and deaths in children under 5 years of age has substantially decreased, as well as the prevalence of PCV13-serotypes. Higher valency PCVs are needed due to the increased prevalence of non-PCV10/13-serotypes. Funding: Gavi, The Vaccine Alliance, reference number: MOZ-HSS-2-INS; WHO Reference: 2014405143-0, creation DFC to support HIB & Surveillance System.

Background In Mozambique, the introduction of a 13-valent pneumococcal conjugate vaccine (PCV13) using a two plus one schedule began in September 2019. However, the replacement of serotypes with non-PCV types remains a concern worldwide following widespread vaccination. We aim to describe the epidemiology of non-PCV13 types among children under 5 years of age with pneumococcal meningitis four years after PCV13 introduction in Mozambique. Methods Between January 2020 and December 2023, a total of 2,014 cerebrospinal fluid (CSF) samples were collected from eligible children as part of the meningitis surveillance system in Mozambique, 103 (5.1%) of which tested positive for S. pneumoniae after triplex qPCR. Among these, 86 (83.5%) samples met the quality criteria for serotyping and were subsequently analysed using sequential quadriplex qPCR. Results Among children under 2 years of age, 84.8% of the S. pneumoniae- positive samples belonged to non-PCV13 serotypes, with serotype 15B/C (31.0%) being the most prevalent, followed by 12F/12A/12B/44/46 (12.1%), 38B (10.6%), and 8 (7.6%). Serotypes 15B/C, 12F/12A/12B/44/46, 38, 8, and 1 were predominant in the northern region of the country (Nampula), whereas serotypes 15B/C and 12F/12A/12B/44/46 were most common in the central region (Sofala). The serotypes coverage of the PCV13, PCV15 and PCV20 vaccine formulations were 20.0%, 26.3% and 75.8%, respectively. Conclusion PCV13 vaccines save many lives in Mozambique. However, they do not seem to be adequate in addresing some of the highly prevailing non-PCV13 serotypes (15B/C and 12F/12A/12B/44/46). Therefore, we suggest that the country's National Immunization Technical Advisory Group (NITAG) review new data and advice on switching to extended valency vaccines such as PCV20.