US National HIV Testing Day boosts numbers testing

Today, June 27, is National HIV Testing Day in the United States and a study just published in Morbidity and Mortality Weekly Report shows that in previous years, this event has resulted in a statistically significant increase in the number of people diagnosed with HIV.

National HIV Testing Day has been observed since 1995 and in recent years HIV testing weeks have also been organised in European and Australasian countries. They encourage health organisations to run events promoting and providing HIV tests.

However there has been some doubt as to whether the events actually have a demonstrable effect on the number of people learning that they are living with HIV. If testing events primarily engaged individuals at low risk of HIV or individuals who would be likely to take a test at a regular health facility on another occasion, they would not achieve this aim.




statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 


An umbrella term for people whose gender identity and/or gender expression differs from the sex they were assigned at birth.

Researchers from Centers for Disease Control and Prevention (CDC) analysed data on HIV testing from 2011 to 2014. They compared data on testing in June (the month in which National HIV Testing Day occurs) with data from other months.

During other times of the year in these four years, the CDC paid for just over a million HIV tests each month. During June, this figure rose by 11% and the number of people being diagnosed with HIV rose by 15%.

A further analysis, looking at testing rates in the two weeks before and after June 27 shows that in each year, the highest number of positive diagnoses was made on National HIV Testing Day. New HIV infections identified on that day, compared with those identified on the next highest day in the period, were 25% higher in 2011, 40% in 2012, 20% in 2013, and 17% in 2014.

The numbers testing increased across all demographic groups. There were particularly impressive increases among gay men and transgender people, suggesting that testing events do reach people at elevated risk of infection. (Nonetheless June is also the month of gay pride events, another occasion when testing events are organised – these may contribute to the data too).

“NHTD [National HIV Testing Day] identifies a number of new HIV infections in populations disproportionately affected by HIV and might increase awareness of HIV status among HIV-infected persons,” the authors conclude. “These findings suggest that community-level approaches to advocate early detection and treatment of HIV infection might use mass testing events such as those promoted for NHTD in areas where HIV is most prevalent.”


Lecher SL et al. Evaluation of the Impact of National HIV Testing Day - United States, 2011-2014. Morbidity and Mortality Weekly Report Jun 24; 65:613-8. (Full text freely available).