Does Circumcision Prevent HIV?


Is circumcision a viable way to prevent HIV?  The short answer is “no.”  Only abstinence and safe sex have the ability to prevent the disease.  It does appear, however, that circumcision may reduce a man’s risk for contracting the disease.

A study published earlier this year on January 6, 2013 in the journal PLoS One found that there are changes in the penis’s microbiome – the community of bacteria that normally reside on the organ – after the foreskin has been removed.

The bacterial flora of the penis changes, they say, because the presence of the foreskin creates an anaerobic environment, allowing types of bacteria not requiring oxygen to grow.  When there is no foreskin to block out oxygen, the microbiome shifts to include more oxygen-loving bacteria.  The researchers believe that the presence of the anaerobic bacteria in uncircumcised men promotes inflammation and increases the odds that the HIV virus will cause an infection.

For the study, a reproductive epidemiologist at Johns Hopkins Bloomberg School of Public Health named Robert Gray worked with other scientists to compare the microbiota of 12 Ugandan men aged 15 to 49 before and after circumcision.  The men selected for the study were HIV-negative.  According to a co-author of the study, Lance Price, who is research director of the Translational Genomics Research Institute in Flagstaff, Arizona, it was important for the men to be HIV-negative since the virus itself would alter the microbiome.

Samples were collected between the head and shaft of the men’s penises both one year before and one year after they were circumcised.  Polymerase chain reaction analysis was performed on the samples in order to identify the types of bacteria in the samples, as well as how abundant they were.

When they analyzed the data, they found that the bacterial populations on the men’s penises had shifted from being primarily aerobic to being anaerobic after they were circumcised.

According to Gray, certain species of bacteria can create an inflammatory environment causing the release of  proteins which regulate immunity called cytokines.  These cytokines activate a type of immune cell called Langerhans cells.  This is significant in the transmission of HIV, he believes, because these activated Langerhans cells are the first cells to become infected by the virus.

The researchers also point out that after circumcision the skin on the penis become thicker, also helping to prevent HIV by reducing the number of Langerhans’s cells which are present.

Despite the fact that circumcision is not a complete preventative measure for HIV – studies indicate that may reduce infections by about 60% – the World Health Organization (WHO) does recommend it as an intervention in countries where there is epidemic HIV but fairly low levels of circumcision.

However, even if researchers can prove that circumcision helps to reduce the transmission of the HIV virus, it cannot be replied upon as the only strategy for preventing infections.  At best, it will only slow down the spread of the illness.  Other measures, such as educating men about the illness and its prevention through safe sex, are still necessary steps.



Written by:  Nancy Schimelpfening

 PLoS One