Invasive meningococcal disease disproportionately burdens Māori and Pacific communities in Aotearoa New Zealand. While meningococci can cause severe illness, they are also carried asymptomatically in the human oropharynx. There is limited information on meningococcal carriage in Aotearoa. To better understand carriage and household transmission, we conducted a carriage study within Māori households in Kaitāia, Northland, and Pacific households in South Auckland. Here, we present genomic analyses of meningococcal carriage isolates from the Pacific South Auckland cohort.
A cross-sectional carriage survey was conducted between May and November 2025, for two cohorts: Pacific households in South Auckland, and Māori households in Te Hiku, Aotearoa New Zealand. Two Pacific households were subsequently recruited into a six-week longitudinal study, with weekly sampling. Oropharyngeal and nasopharyngeal swabs were collected to assess carriage of Neisseria meningitidis and Streptococcus pneumoniae. Carriage of meningococci were assessed by real-time porA PCR and culture. Carriage isolates were sequenced and compared with contemporary invasive disease isolates. Transmission within households was assessed using single nucleotide polymorphisms analysis.
A total of 700 participants from 104 households were recruited. Overall meningococcal carriage was 17.3% and highest among those aged 15−24 years (25.4%). Adjusted analyses showed increased odds of carriage in this age group (aOR 2.9, 95% CI 1.2–6.6), as well as associations with recent social mixing and bed sharing. Sixty-five isolates were cultured in total. Group B meningococci were the most common among the carriage isolates, followed by non-capsulated, group C, group W and group Y meningococci. The most common group B variant, B:P1.7-12,14:cc1572, is also the most common invasive B meningococci in 2025. SNP analysis of isolates within households and from the longitudinal study showed direct transmission among household members as well as separate introductions of different lineages.
To our knowledge, this study is first of its kind conducted in New Zealand. It provides a baseline for future carriage studies, and it demonstrates the importance of community support and culturally grounded methods in public health studies. Result obtained could lead to better understanding of pattern of transmission within households and as well inform equitable public health interventions and vaccination strategies.