Reactive vaccination as a control strategy for pneumococcal meningitis outbreaks in the African meningitis belt: Analysis of outbreak data from Ghana

Abstract

Streptococcus pneumoniae is increasingly recognised as an important cause of bacterial meningitis in the African meningitis belt. The World Health Organization sets guidelines for response to outbreaks of meningococcal meningitis, but there are no current guidelines for outbreaks where S. pneumoniae is implicated. We aimed to evaluate the impact of using a similar response to target outbreaks of vaccine-preventable pneumococcal meningitis in the meningitis belt. Here, we adapt a previous model of reactive vaccination for meningococcal outbreaks to estimate the potential impact of reactive vaccination in a recent pneumococcal meningitis outbreak in the Brong-Ahafo region of central Ghana using weekly line list data on all suspected cases over a period of five months. We determine the sensitivity and specificity of various epidemic thresholds and model the cases and deaths averted by reactive vaccination. An epidemic threshold of 10 suspected cases per 100,000 population per week performed the best, predicting large outbreaks with 100% sensitivity and more than 85% specificity. In this outbreak, reactive vaccination would have prevented a lower number of cases per individual vaccinated (approximately 15,300 doses per case averted) than previously estimated for meningococcal outbreaks. Since the burden of death and disability from pneumococcal meningitis is higher than that from meningococcal meningitis, there may still be merit in considering reactive vaccination for outbreaks of pneumococcal meningitis. More outbreak data are needed to refine our model estimates. Whatever policy is followed, we emphasize the importance of timely laboratory confirmation of suspected cases to enable appropriate decisions about outbreak response.

Evaluation of pneumococcal meningitis clusters in Burkina Faso and implications for potential reactive vaccination

“…This analysis adds to the growing literature regarding pneumococcal meningitis in the context of PCV implementation in West Africa [8] , [20] , [21] , [23] , [24] , [25] , [27] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , from a country with nationwide population-based surveillance data with routine pneumococcal serotyping [15] , [16] , [18] . Following the successful introductions of Hib vaccine and MACV, the epidemiology of bacterial meningitis in the meningitis belt is changing and S. pneumoniae is increasingly recognized as causing a high proportion of remaining disease [9] .…”

“…Finally, during our limited years of observation, we did not detect any pneumococcal meningitis outbreaks in Burkina Faso similar in size to those recently reported in Ghana [8] , [25] . Therefore, this analysis is unable to help inform models of pneumococcal meningitis outbreaks in the meningitis belt [27] .…”

“…Unlike for meningococcal meningitis, there is no formal epidemic definition or outbreak response guidelines for pneumococcal meningitis [26] . These experiences prompted discussions about potential methods to prevent and respond to pneumococcal meningitis outbreaks in the meningitis belt [27] . To help inform these discussions, we retrospectively examined Burkina Faso’s case-based meningitis surveillance data to identify and describe pneumococcal meningitis clusters.…”

Seasonal upsurge of pneumococcal meningitis in the Central African Republic

“…Serotype 1 is among the serotypes targeted by PCV10 and PCV13. Establishing the serotype of pneumococcal meningitis during an outbreak is crucial for establishing an appropriate control strategy, such as reactive vaccination 21, 22 .…”

Analysis of a meningococcal meningitis outbreak in Niger – potential effectiveness of reactive prophylaxis

“…Several papers have examined the effect of different intervention thresholds on effectiveness of interventions for seasonal meningitis outbreaks[15–18]. These studies have focused on reactive vaccination, which typically has a lag time of weeks between crossing the epidemic threshold to implementation.…”