The risk of meningococcal infection among homosexuals is 4 times higher than that of heterosexuals. HIV-infected homosexuals have a 10-fold higher risk of meningococcal disease than uninfected homosexuals. 45% of meningococcal cases reported numerous partners and participation in anonymous sex.
Among homosexuals, 32% smoke (compared to 18% of adults in the US), and 48% use drugs (compared to 10% on average).
In New York, the risk of meningococcal infection among homosexuals was 50 times higher than, on average, in German and 13 times above, in Paris 10 times above, in Southern California 50 times higher. 24% of homosexuals are carriers of meningococcus compared with 6% among heterosexual women, among the homosexuals who recently had oral-anal contact, 43% were carriers. Meningococcus was also detected in 4.5% of homosexuals in the anal channel. In 2016 there was a discovered a new strain of meningococcus that can be transmitted sexually.
CDC reports that in 2016, 57% of those meningococcal men over 16 years of age reported having a homosexual contact. More:   .
HIV infection increases the risk of meningococcal infection 11-fold, and AIDS 12-fold. In 2010, a new outbreak of meningococcus among homosexuals began in New York City, due to mobile dating applications and visits to gay bars.Outbreak of hepatitis A associated with men who have sex with men (MSM), England, July 2016 to January 2017. 2017, Beebeejaun, Euro Surveill
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. Connected with the gay parade in Amsterdam.
Hepatitis A outbreak in Leon 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.