A study, published in PLoS Pathogens, also found transmission clusters in the heterosexual population occurred in networks of more than 10 people and as many as 30 people, but were smaller than those found among HIV-infected homosexual men.
"The slower dynamics of the heterosexual epidemic thus offer more opportunity for successful intervention, but it is essential that diagnosis is achieved as early as possible," study leader Andrew Leigh Brown of the University of Edinburgh said in a statement.
The study, based on Great Britain's HIV Drug Resistance Database of viral DNA sequence information from more than 30,000 infected individuals, looked at virus gene sequences from more than 11,000 infected individuals.
This represented 40 percent of the HIV-infected heterosexual population in the United Kingdom. Most infected heterosexuals were immigrants from sub-Saharan Africa, the researchers said.