Wednesday September 27 2017

“HIV rises among over-50s as they neglect safe sex” is the headline from The Times.

The news is based on a European study that found more over-50s are being diagnosed with HIV compared with 12 years ago.

The study collected data on more than 360,000 people who had been newly diagnosed with HIV between 2004 and 2015 in Europe.

The researchers looked at infection rates over time according to age, route of transmission and country.

They found a number of differences between the patterns of infection and diagnosis in those aged 15 to 49 and in those aged 50 and over.

In the over-50s age group, though people remained more likely to become infected with HIV through heterosexual sex, the rate of infection in men who have sex with men and through drug injection had increased between 2004 and 2015.

But in younger adults, infection rates hadn’t changed over time and men having sex with men remains the most likely route of transmission.

Older people were also more likely to be diagnosed when the disease was advanced compared with younger people.

This study highlights the need for people of all ages to be aware of the risks of HIV infection from unprotected sex.

HIV tests are free on the NHS and can be done in various places, including walk-in sexual health clinics. There are also home testing kits available.

Find out more about HIV tests and find HIV testing services near you.

Where did the story come from?

The study was carried out by researchers from the European Centre for Disease Prevention and Control in Sweden in collaboration with members of the European Union/European Economic Area HIV Surveillance Network.

It was funded by the European Centre for Disease Prevention and Control.

The study was published in the peer-reviewed journal The Lancet. The abstract is available free online.

Some of the media stories suggested the rise in HIV cases among older people was because this age group neglected messages about safer sex.

Mail Online went as far as saying: “Reckless sexual behaviour by divorcees is behind an increase in HIV cases among the over-50s, a major study suggests”.

But the study didn’t report on marital or relationship status, and didn’t investigate sexual behaviour.

Several stories also focused on the number of older people who have been infected through heterosexual contact.

While heterosexual sex is the most likely transmission route for the over-50s age group, these rates have remained stable over the last 12 years.

It’s the rate of infection from sex between men and from drug injection that has increased over time for this age group.

What kind of research was this?

This was an observational study using data sent by EU and EEC member states to the European Surveillance System for HIV.

This type of study is useful for identifying trends in diagnosis rates, but relies on accurate data reporting and collection.

Actual rates of HIV may be higher, as this only takes into account people who have had a positive test.

What did the research involve?

The researchers collated data from 31 countries on new cases of HIV diagnosed between January 2004 and December 2015.

The data was anonymised, but included:

  • date of diagnosis
  • age
  • sexual history
  • mode of transmission
  • country of birth
  • country of diagnosis
  • stage of disease according to CD4 count, with late diagnosis defined as less than 350 cells/µL and advanced disease as less than 200 cells/µL

They analysed the data according to two age groups: younger people aged 15 to 49 and older people aged 50 or over.

What were the basic results?

Overall, between 2004 and 2015:

  • There were 312,501 new cases of HIV in people aged 15 to 49, a rate of 11.4 per 100,000 people. This rate of infection didn’t change over time.
  • There were 54,102 new cases of HIV in adults over 50, a rate of 2.6 per 100,000 people. The rate of infection increased by 2.1% per year over the 12-year period.

In the UK:

  • There was an increase of 3.6% in new diagnosis rates for older people between 2004 and 2015, from 3.1 to 4.32 new cases per 100,000 people. This is higher than the European average.
  • There was a 4% reduction in new diagnosis rates for younger adults during this time.

Diagnosis by age group:

  • Older people were more likely to have a delayed diagnosis, with significantly lower CD4 counts than younger adults.

Men compared with women:

  • Over the 12-year period, the average diagnosis rate for older men increased from 3.5 to 4.8 per 100,000, while older women had an increase from 1.0 to 1.2 per 100,000.
  • Over the same period, the average rate of diagnosis increased by 1.4% in younger men and reduced by 4.8% for younger women.

Mode of transmission in 2015:

  • The most common route of infection for older adults was heterosexual contact (42.4% of cases), followed by sex between men (30.3%), “other” or unknown causes (24.6%), and injecting drugs (2.6%).
  • For younger adults, sex between men was the most common route of infection (45.1% of cases), followed by heterosexual contact (30.8%), other or unknown (19.5%), and injecting drugs (4.6%).

Changes in mode of transmission from 2004 to 2015:

  • The rate of HIV infection from heterosexual sex remained stable in older people, and decreased in younger people.
  • Infection resulting from injecting drugs increased in older people and decreased in younger people.
  • The rates of HIV infection in men who have sex with men increased in both age groups, but more so in older people at 5.8% compared with 2.3%.

How did the researchers interpret the results?

The researchers concluded that the “increasing new HIV diagnoses among older adults point towards the compelling need to heighten awareness among healthcare providers and deliver more targeted prevention interventions for this age group and the total adult population”.

They were also careful to say that “no data for the reasons behind such an increase [in new HIV diagnoses in older people] have been published”.

Conclusion

This was a well-conducted study and the results are likely to be reliable, though there are some limitations, including missing data.

For example, the researchers had no information on the migration status or CD4 count (an indicator for stage of the disease) for a quarter of cases.

This study found that although the overall rate of infection is higher in younger people, this has remained stable over the last 12 years while the rate of infection in older people has increased.

Some of the media stories focused on the finding that older people are most likely to have become infected through heterosexual sex.

While true, this is nothing new: the rate of infection from heterosexual sex has in fact been stable for over-50s over the study period, whereas the rates of infection in men having sex with men and drug use have both increased for this age group.

What makes further analysis of this trend difficult to interpret is the high proportion of people for whom “other” or “unknown” infection was recorded.

The finding that older people were more likely to have a delayed diagnosis highlights the importance of HIV testing for people of all ages who are at risk of infection.

What’s of most concern is that the rates of infection remain high in all age groups despite public health campaigns about practising safe sex.

HIV tests are free on the NHS and can be done in various places, including walk-in sexual health clinics. There are also home testing kits available.

Find out more about HIV tests and find HIV testing services near you.