Background: Mozambique introduced 10-valent pneumococcal conjugate vaccine (PCV10) in 2013 using three-dose schedule without a booster, in 2017 switched to PCV13, using two plus one schedule. We assessed long-term impact of PCV on disease incidence in Mozambique and the impact of PCVs and schedule changes.
Methods: We analysed meningitis surveillance data in Mozambique from March 2013 through December 2023. Cerebrospinal fluid (CSF) samples were collected from eligible children in three referral hospitals in Mozambique. Culture and polymerase chain reaction assay (qPCR) were performed on each sample. S. pneumoniae positive samples were serotyped using multiplex PCR. We estimated annual incidence rates pneumococcal meningitis in children under five following PCVs introduction. The impact of product switch and schedule change was assessed.
Findings: 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 to 4.6 cases per 100,000 person-years in 2013 and 2023, respectively, an 89.7% reduction. In the PCV13/2p+1 period-(2020-2023) disease incidence was 51.2% lower than PCV10/3p+0 period-(2013-2017) (IRR:0.5[95%CI:0.4–0.6];p<0·001). PCV10-serotype incidence decreased 65.6% during PCV13/2p+1 period(IRR:0.3[95%CI:0.2–0.6];p<0.001). We detected zero cases of pneumococcal meningitis due PCV13-serotype in 2020–2023, whereas non-PCV10/13-serotypes increased 52.6% (IRR:1.8[95%CI:1.2–2.6];p=0.004). The case-fatality proportion decreased 71.9% (95%CI:62.9%-84.8%) during PCV13/2p+1 period.
Interpretation: Routine introduction of PCVs substantially decreased the burden of pneumococcal meningitis and deaths among children under five in Mozambique, including the prevalence of PCV13-serotypes. Higher valency PCVs are needed due to increased prevalence of non-PCV10/13-serotypes