The actual figure for 2015, included in just released data, is likely to be slightly higher than 153 as a small group of people for whom the means of transmission is unknown are likely to include several men who have sex with men. In 2013 the minimum figure was 114 and 2014 saw a minimum of 136 newly-diagnosed infections.
It is not known with certainty how long any of the men had been infected before their 2015 diagnosis and the continuing second surge since the year 2000 could to some degree reflect a higher incidence of HIV testing by gay and bi men. However, researchers say "the persisting increase in recent infections being diagnosed together with the increase in total diagnoses suggests a true increase in incidence in recent years." 58% of gay and bisexual men diagnosed in 2015 had a low CD4 cell count, an indication of how HIV has impaired the immune system, which indicates they had been living with the virus long term. This is an increase from 53% in the previous year.
Of the 153 men newly-confirmed to have HIV 33 had previously been diagnosed with the incurable virus overseas but statisticians at the AIDS Epidemiology Group at the University of Otago who generate the annual HIV and AIDS reports say locally-contracted HIV infections continue to rise.
1699 men, most of whom will be gay or bisexual, are currently being treated for HIV infection in New Zealand. The NZ AIDS Foundation believes there could be as many as 600 gay or bi men who have HIV but don't yet know it.
A small, brighter note in the data shows that the number of people progressing from HIV infection to having AIDS continues to drop significantly, as does the death rate from an epidemic which, at its most fatal in the late 1980s and early 1990s was killing between 60 and 75 gay and bi men a year. The annual AIDS and death numbers are both now in the single digits.