HIM (HPV In Men) Study

The peak seropositivity for HPV vaccine types is in women 30-39 years of age and is approximately 40% according to data compiled by both the United States and Australia. The antibody levels decrease after that age.

Non-Hispanic blacks have the highest seroprevalence amongst both females and males. There was, however, no significant difference by race/ethnicity for HPV 16 seroprevalence amongst females.

Seroprevalence types for HPV vaccine types were higher in Australia reaching 32% (at 40-49 years) compared to 18% (at 50 – 59 years) in the United States.

There is a higher incidence of HPV in men when compared to women.

The median time to clearance of HPV 16 is nearly 2 x longer (approximately 12 months) compared to that of HPV 18 (approximately 6 months). The longer median clearance time of HPV 16 compared to 18 has been observed to occur in women as well as men.

Higher exposures (e.g., a large number of sexual partners) may require in men to produce an immune response that gives them more protection against subsequent infections. Observation has been made that the clearance of HPV infections is increased in men who have a greater number of lifetime partners.

Men have a lower prevalence to antibodies to HPV than do women despite the fact that men have higher genital HPV prevalence. Those men who do have a certain amount of HPV antibodies have titers (levels) that are much lower than women.

Seroprevalence is highest for HPV 16, a person who has antibodies for all four types, and seroprevalence is higher amongst females than amongst males.

HPV antibody level data has limitations of interpretation of cumulative exposure. Only approximately 60% of people exposed to HPV actually generate antibodies, and the antibody levels can tend to wane and go down over time.

Lifetime number of sexual partners is a strong predictor for positive antibody levels in men.

Age and lifetime number of sexual partners is associated with positive antibody levels in men.

Age, lifetime number of sexual partners and positive level are significant risk factors for positive HPV antibody levels in women.

There is a faster clearance of high risk HPV infections in men with increase in age.

The fact that most people are not exposed to all four HPV vaccine types indicates that traditional people may be ultimately protected HPV infections.

The more rapid clearance noted in older men might be related to a higher prevalence of HPV antibodies in older men.

The risk of HPV decreases with increased in age in women.

Data about the incidence of clearance of HPV infection in men is essential for the development of realistic cost/-effective ________ of male HPV infections all over the world.

Serologic data for males may be less useful than those in female whose lower seroconversion rates because fewer men generate antibodies after infection and men demonstrate the presence of antibodies for a shorter period of time (antibody persistence) which makes the interpretation of men cumulative exposure over a lifetime more challenging.

Men have a stable risk for acquiring a new HPV infection throughout their lifetime.
In a study of men in the United States, the incidence of HPV infection was constant with the age range of 18-44 years of age. The incidence of HPV infection is also found to be constant in men age 18-70 years old living in Brazil, Mexico and the United States.

Men continue to be at high risk for acquiring new HPV infections throughout their lifetime. Then the vaccination of men at ages over the current guidelines (up to 26 years of age) might be warranted.

Only 17% of women were seropositive to over one HPV strain.

HPV infections of the keratinized epithelium of the skin on the penis generates a lower and weaker immune response that infection of mucosal epithelium such as in the cervix or in the anal canal.

HPV infection of keratinized epithelium in men may be less likely then an infection in the mucosal surfaces (such as in the anal canal) to introduce an immune response. In addition, the lower antibody levels in men may be because the duration of infection in men is shorter and the antibodies are less likely to develop after exchanging an HPV infection. The differences in the persistence of antibodies are a contributory factor. In men and women who had approximately equal rates of acquisition of high risk HPV 16, a lower percentage of males than females were seropositive six months after they acquired in the infection (39% versus 62%).

The lower seroprevalence among men is probably due to differences in immune response induced by HPV infection rather than to lower infection rate. There is actually a higher prevalence of HPV among men than women.