What is the prevalence of Herpes Simplex Virus type 1 (HSV1) and Herpes Simplex Virus type 2 (HSV2) in New Zealand?

From the Guidelines

Herpes Simplex Virus is common in New Zealand, with HSV-1 affecting approximately 60-70% of the adult population and HSV-2 affecting about 12-15% of adults, based on similar prevalence rates in other developed countries such as Australia 1. The prevalence of HSV-1 and HSV-2 in New Zealand can be estimated from studies in similar populations.

• HSV-1 typically causes oral herpes (cold sores) but can also cause genital infections, while HSV-2 primarily causes genital herpes.
• Many people with herpes remain undiagnosed because infections are often asymptomatic or have mild symptoms that go unrecognized.
• The virus is transmitted through direct contact with infected skin or mucous membranes, with HSV-1 commonly spread through oral contact and HSV-2 through sexual contact.
• Once infected, the virus remains dormant in nerve cells for life, with periodic reactivations possible.
• Prevention includes avoiding contact during outbreaks, using condoms, and antiviral medications like acyclovir, valacyclovir, or famciclovir which can reduce transmission risk and outbreak frequency but cannot cure the infection.
• The experience with antiviral medications in New Zealand, such as the reclassification of famciclovir from a prescription-only medicine to a restricted medicine, has shown that pharmacist-controlled purchase of oral antivirals can be effective in treating herpes labialis 1.
• However, it is essential to note that the prevalence rates of HSV-1 and HSV-2 in New Zealand are not directly reported in the provided studies, and the estimates are based on similar prevalence rates in other developed countries.
• Further studies are needed to determine the exact prevalence rates of HSV-1 and HSV-2 in New Zealand.

From the Research

Prevalence of HSV1 and HSV2 in New Zealand

• The prevalence of Herpes Simplex Virus type 1 (HSV1) and Herpes Simplex Virus type 2 (HSV2) in New Zealand can be understood through various studies, including 2 and 3.
• According to 2, the pooled mean seroprevalence of HSV1 among healthy adults in Australia was 84.8%, and it is likely that the seroprevalence in New Zealand is similar, given the geographic proximity and similar demographic characteristics.
• A study on the epidemiology of HSV2 in Canada, Australia, and New Zealand 3 found that the combined pooled mean seroprevalence of HSV2 among general populations in Australia and New Zealand was 15.4%.
• Another study 4 found that the seroprevalence of HSV2 in a cohort of 26-year-old New Zealanders was 11%, with an annual seroconversion rate of 13.5 cases per 1000 per year.
• A global review of age-specific prevalence of HSV1 and HSV2 infections 5 found that HSV2 prevalence is generally higher in women than men and in populations with higher risk sexual behavior.

HSV1 Prevalence

• The study 2 found that the pooled mean seroprevalence of HSV1 among individuals <35 years of age was 70.2%, and among individuals ≥35 years was 86.9%.
• The seroprevalence of HSV1 increased by 1.05-fold per year, indicating a potential increase in the prevalence of HSV1 over time.

HSV2 Prevalence

• The study 3 found that the pooled mean proportion of HSV2 isolation in laboratory-confirmed genital herpes was 71.9% in Australia and New Zealand.
• The proportion of HSV2 isolation in genital herpes declined by 0.98-fold per year, indicating a potential decrease in the role of HSV2 in genital herpes over time.
• The study 4 found that new HSV2 infections were associated with female sex and an early age of first intercourse, highlighting the importance of sexual behavior in the transmission of HSV2.