Men who have sex with men (MSM) have an increased risk of meningococcal disease, investigators from the United States report in the online edition of Clinical Infectious Diseases. The number of cases was small, but overall incidence of meningococcal disease was four times higher among MSM compared to non-MSM, with the risk especially high for HIV-positive MSM.
â€śWe demonstrated that although incidence is low, the relative risk of meningococcal disease is higher among MSM than the non-MSM male population in the United States, with HIV infection identified as a likely factor for this increased risk observed among MSM,â€ť comment the authors. They believe their findings support recommendations for all HIV-positive people to receive the quadrivalent meningococcal vaccine.
The findings coincide with a recommendation from the Global Meningococcal Initiative that all people living with HIV should be vaccinated. The Global Meningococcal Initiative is an international scientific expert panel; its review of the scientific literature and recommendations for action were published last week in the Journal of Infection. The panel highlighted the need for national vaccination programmes to include people living with HIV in sub-Saharan Africa where the prevalence of meningococcal disease is high, and also drew attention to recent outbreaks among men who have sex with men.
Meningococcal disease is a serious bacterial infection caused by Neisseria meningitidis. The bacteria can be transmitted in saliva, through kissing or sexual contact, or through close and prolonged household contact. The typical symptoms of infection are the sudden onset of fever, severe headache and stiff neck, often accompanied by sensitivity to light, confusion and nausea.
Clusters of the infection were recently reported among MSM in New York City, Los Angeles and Chicago. Many of the affected MSM were HIV-positive.
Investigators wanted to establish a clearer understanding of the overall burden and risk of meningococcal disease among MSM in the United States.
Data from the National Notifiable Disease Surveillance System were examined to identify all cases of the infection reported in men aged between 18 and 64 years between 2012 and 2015. Incidence and risk was compared between MSM and non-MSM. Samples of bacteria from infected MSM were examined to identify the meningococcal serotype and to see if the infections were genetically linked.
A total of 527 cases of the disease were identified. Of these, 74 (14%) were in MSM, with 63% of these infections reported in the three cities where clusters of meningococcal disease involving MSM have been identified. Approximately 60% of cases in MSM involved men with HIV infection.
A large proportion of cases in MSM involved men aged between 26 and 35 years (43%), whereas the 18 to 25 years age bracket was the group most affected in non-MSM (31%).
Neisseria meningitidis serogroup C accounted for 85% of cases in MSM but just 26% of cases in non-MSM.
The MSM had a high prevalence of risk factors for meningococcal infection (which is often contracted via contact with infected saliva), with 32% reporting smoking, 49% the use of recreational drugs including cannabis and 45% multiple sexual partners.
Genome sequencing suggested transmission networks among the clustered cases of the infection among MSM in Chicago, Los Angeles and New York, with many of the cases genetically linked.
Overall incidence of the disease was 0.56 cases per 100,000 persons among MSM compared to 0.14 per 100,000 persons among non-MSM.
MSM therefore had a fourfold increase in their relative risk of the infection (CI, 31.-5.1, p < 0.01). Risk varied according to geographic region. In areas outside the clusters, the relative risk was doubled for MSM (p < 0.001), but was between 15 and 32 times higher in the three cluster cities.
MSM with HIV had 10.1 times the relative risk of meningococcal disease (95% CI, 6.1-16.6, p < 0.001) compared to non-MSM, with the risk especially high in the three cities with clusters of the disease (RR 12.7; 95% CI, 5.1-31.9, p < 0.001).
â€śWhile this evaluation demonstrates the increased risk of disease among MSM, further study is needed to better understand the transmission and risk factors in this population in order to inform public health prevention and response strategies,â€ť conclude the investigators. â€śClinicians and public health authorities should continue to increase awareness of meningococcal disease among MSM, identify vaccination strategies and other public health measures to protect MSM during outbreaks of meningococcal disease in this population, and encourage routine vaccination of all HIV-infected MSM with a quadrivalent meningococcal conjugate vaccine.â€ť
A small outbreak of meningococcal disease among men who have sex with men was reported in Germany, Belgium and France in 2013. French public health authorities subsequently recommendedthat all men who have sex with men over the age of 25 should be vaccinated, as should anyone else attending gay social venues.
Current United Kingdom guidance, published by the British HIV Association in 2015, is that people living with HIV should be offered vaccination against meningoccocal disease according to the same criteria as the rest of the population. People under 25 who are not yet vaccinated, and people with asplenia or complement component deficiency (a lack of proteins involved in early responses to infections) should be vaccinated, the guidelines recommend. Those at risk of exposure through travel or recent contacts should also be vaccinated. Travellers to cities or countries where a current outbreak is reported or where meningococcal disease is common (e.g. central Africa) should discuss vaccination with their clinic.