Health chiefs are using National HIV Testing Week as an opportunity to urge those at risk of HIV to order a free test.
Brighton and Hove has one of the highest rates of HIV in the country, with 7.94 affected per 1,000 people aged 15 to 59, or more than 1,500 cases.
The rate locally is more than three times the England average of 2.39 and more than four times the south east regional average of 1.88.
Brighton and Hove also has more than twice the infection rate of places such as Reading (3.45) and Slough (3.38).
Public Health England (PHE) said: “Where there is more cause for concern is the high rate of late diagnosis.
“The danger of being diagnosed late is that an individual may have unwittingly infected a greater number of other people and have also been without vital treatment, thereby shortening their own life expectancy.
“Just under half of those who tested positively in the south east (48.5 per cent) were diagnosed late.”
Brighton and Hove has one of the lowest rates of late diagnosis in the south east.
PHE said: “Making access to HIV testing easy and convenient is key, as is tackling the stigma that is still associated with HIV if more people are to choose to take a test.
“New figures from PHE show that between January and August last year there was a 14 per cent increase in HIV testing done via online orders and taken at home compared to the same period in 2019.
“But there is still a need to better publicise the option to test for HIV at home. Just 16 per cent of UK adults knew they could test for HIV at home.
“It is critical that anyone who is at risk of HIV, such as those living in high-prevalence areas or who have recently had sex with a new partner, men who have sex with men (MSM) and the black African community, get tested as soon as they are able to and regularly in the future.
“Those diagnosed early can have a life expectancy almost matching that of people who are HIV-free.”
National HIV Testing Week runs from Monday (1 February) to Sunday (7 February).
Public Health England said: “PHE has made available thousands of self-sampling kits and is urging those most at risk in the south east to order a free HIV postal test or to get themselves tested locally.”
PHE South East’s health and wellbeing programme lead Jason Mahoney said: “During the pandemic and throughout lockdowns, people have been changing their sexual behaviour.
“The positive thing about the current situation is that there are more opportunities to get testing online and you can do it from the comfort of your own home.
“I would urge everyone who thinks they might be at risk to get a free HIV test this week – a simple finger-prick test.
“It’s delivered to your door, you receive the results electronically and if it’s positive you’ll get referred to local services for support and treatment. The sooner you can start treatment the better.”
PHE said: “For anyone testing positive, it is important to remember that the quality of HIV care and treatment continues to be excellent in the south east and across the UK.
“In 2018, 94 per cent of people in the UK living with diagnosed HIV and accessing HIV treatment were virally suppressed and cannot pass on the virus.
“For more information on National HIV Testing Week, and to order a free testing kit visit https://freetesting.hiv.
“Free testing is available outside of this time through local services visit https://startswithme.org.uk to find out where to test locally.”