The risk of meningococcal infection in homosexuals in 4 times higher, than in heterosexual people. HIV positive homosexuals suffer from meningococcal disease 10 times more often, than HIV negative ones. 45% of meningococcus patients reported multiple partners and participation in anonymous sex.
Among homosexuals, 32% smoke (as compared to 18% among adults in the USA), and 48% are drug users (as compared to an average of 10%).
In New York and Southern California, the risk of meningococcal infection among homosexuals was 50 times higher, than in general; in Germany, it was 13 times higher; and in Paris – 10 times higher.
24% of homosexuals are carriers of meningococcus, as compared to 6% of heterosexual women. Among homosexuals, who have had oral-anal contact recently, 43% were carriers.
Meningococcus was also found in the anal canal in 4.5% of homosexuals.
A new strain of meningococcus that can be transmitted sexually was discovered in 2016.
CDC reports that in 2016, 57% of men over 16 years of age infected with meningococcus, reported homosexual relations. More:   .
HIV infection increases the risk of meningococcal infection by 11 times, and AIDS increases the risk by 12 times.
A meningococcus outbreak among homosexual began in New York in 2010. This is connected to the mobile dating apps and attending gay-bars.
In 2016-17, major European cities were overwhelmed with hepatitis A outbreaks. The vast majority of cases were homosexuals. 37 cases were registered in England.
46 cases were registered in a Barcelona hospital. 96% of them were men, and 67% identified themselves as homosexuals. The authors write that the main risk factor is the oral-anal contact during sex, that most recent outbreaks in Europe happened between 2008 and 2011, and that because of these outbreaks, hepatitis A was classified as an STD.Ongoing outbreaks of hepatitis A among men who have sex with men (MSM), Berlin, November 2016 to January 2017 - linked to other German cities and European countries. 2017, Werber, Euro Surveill
Outbreak in Berlin. 38 cases, 37 men, 30 reported homosexual relationships. The woman also reported same-sex relationships. One of the patients was vaccinated 11 months prior to the onset of the disease.
Outbreak in Rome and surrounding area. 513 cases, 87.5% of them men.
Outbreak in Tel Aviv. 19 cases, 17 of them homosexuals. 
Altogether, 1,500 cases of hepatitis A were registered in 16 European countries, and 2,600 unconfirmed cases, mainly among homosexuals.
11,212 cases of disease were registered in Europe between January and August, 2017, mainly among homosexuals.
The WHO also reports an outbreak among homosexuals in Chile.
It all started with a gay parade in Amsterdam in 2016, which attracted half a million visitors. A total of 48 cases were registered among men in Netherlands.
Outbreak in Osaka, Japan, in 2018. 13 cases, all homosexual. Linked with the gay parade in Amsterdam.
Hepatitis A outbreak in Lyon in the first half of 2017. 46 cases, 38 of them men, 33 homosexuals, and 15 HIV positive. Most of them have been vaccinated or had antibodies.
According to the existing model, 70% of those with immunity would be enough to prevent hepatitis A infection among homosexuals. The authors conclude that 70% is not enough.
It is also reported that since contracting hepatitis A is also possible from needle sharing, slamming (intravenous drug use during anal contact), a practice that is gaining popularity among certain homosexual groups, can also increase the risk of infection. More: , .
Outbreak of hepatitis A in Taiwan. More than 1,000 cases, 70% of them homosexuals, 60% HIV positive, and more than 60% infected with syphilis, gonorrhea or shigellosis.
There are no mentions of deaths from hepatitis A in any of these outbreaks.