MODELLING THE IMPACT OF COVID-19 AND ROUTINE MENACWY VACCINATION ON MENINGOCOCCAL CARRIAGE AND DISEASE IN THE UK.

INTRO: Enforced country-wide social distancing and suspension of most non- emergency medical care due to the COVID-19 pandemic will undoubtedly affect public health in multiple ways. While non-pharmaceutical interventions are expected to reduce transmission of several infectious diseases, severe disruptions to healthcare systems have hampered diagnosis, treatment, and routine vaccination. We examine the pre-pandemic community carriage prevalence together with the effect of this disruption on meningococcal disease and vaccination in the UK. METHODS: By adapting an existing mathematical model for meningococcal carriage and disease, we address the following questions:a) What is the predicted impact of the adolescent MenACWY vaccination on meningococcal transmission pre-pandemic? b) What is the predicted impact of social distancing on current infection rates? c) What effect might reductions in vaccine uptake have on future infection rates? d) Will catch-up vaccination campaigns be necessary for the MenACWY vaccine? FINDINGS: Model findings indicate that the MenACWY vaccine programme was already generating indirect protection and supressing transmission. Even without pandemic modelling assumptions, we observe that carriage prevalence could approach near-elimination in around 30 years due to the new lower community carriage prevalence observed by UKMenCar4 and effects of the 2015 MenACWY catch-up campaign. Moreover, COVID-19 social distancing is expected to have accelerated the decline, causing significant long-lasting reductions in the carriage prevalence of meningococcal strains A, C, W, and Y leading to near- elimination in under 20 years. CONCLUSION: In all scenarios modelled, pandemic social mixing effects outweighed potential reductions in vaccine uptake (of up to 50%) causing an overall decline in carriage prevalence.