The numbers of people over 50 infected with HIV in the UK has more than doubled over the past seven years, showing that this age group is as much at risk from unsafe sex as the young, the Health Protection Agency warned on Wednesday.
In England, Wales and Northern Ireland there were 299 new HIV infections among the over-50s, according to the HPA, which presents its findings at the International Aids conference in Vienna today. But in 2007 there were 710 new cases, an increase of 60 per cent.
Some of those diagnosed after the age of 50 will have been infected when they were younger and diagnosed late. After some early symptoms, people who are fit and healthy often continue to feel well and may not suspect they have HIV for as long as 10 years. Unfortunately, late diagnosis reduces their chances of survival.
But half of the over-50s diagnosed had recently been infected, suggesting they had been taking chances.
Compared with younger adults carrying the virus, older people were significantly more likely to have been infected through sex with men. Older "straight" adults were more likely to acquire the virus in the UK, but there was evidence of white heterosexual men picking up the infection abroad.
"This highlights the importance of HIV testing, whatever your age," said Ruth Smith, a senior HIV scientist at the HPA's Centre for Infections. "We must continually reinforce the safe sex message - using a condom with all new or casual partners is the surest way to ensure people do not become infected with a serious sexually transmitted infection such as HIV."
Her co-author, Valerie Delpech, head of HIV surveillance at the HPA, said people in the older age group needed to be aware that they were just as much at risk as young people if they had unsafe sex.
"Although adults aged 50 and over account for just 8 per cent of all new HIV diagnoses, the fact that cases have more than doubled in recent years serves as a timely reminder that anybody is at risk of HIV infection if they do not use protection and practise safe sex," she said.