- Laboratory-based syphilis testing takes time and can necessitate follow-up clinic visits for treatment
- A study with more than 1,000 people found that rapid tests were highly accurate, with results in minutes
- Rapid tests have the potential to make initiation of treatment for syphilis and HIV faster
Canada is undergoing a sustained resurgence of syphilis with a wide range of populations affected. If left undiagnosed and untreated, syphilis can cause serious complications in adults and in infants of infected parents, as well as in the fetus of a pregnant person.
Syphilis is typically diagnosed with a blood sample sent to a laboratory. If the sample tests positive, a single course of treatment is usually effective at curing syphilis in most people.
When lab-based testing is used, it may take a week or longer before results are sent to a healthcare provider’s office and the patient is notified. The patient then has to go to a clinic to get a prescription and/or receive treatment. All of these steps delay the initiation of treatment.
People who have a sexually transmitted infection (STI) such as syphilis may also be at risk for other STIs, including HIV. People with newly acquired HIV may also have syphilis. Therefore, ideally, it makes sense to provide simultaneous testing for at least these two STIs. A test kit that can analyse a sample of blood for both STIs could speed up diagnosis of these infections as well as entry to care and initiation of treatment.
In Alberta
A team of researchers in Alberta conducted a clinical trial to evaluate two rapid test kits (which did not require complex laboratory equipment) for syphilis and HIV. The researchers evaluated results from more than 1,000 participants from the following sites:
- an STI clinic
- an inner-city hospital’s emergency department
- an urgent care centre
- a correctional facility
- a First Nation community
The researchers used the following two rapid syphilis-HIV test kits:
- Multiplo TP/HIV test made by MedMira
- INSTI multiplex HIV-1/HIV-2/syphilis test made by bioLytical Laboratories
For these tests, blood from a finger prick was used. Healthcare providers, mostly nurses, administered the tests. Participants also gave a standard blood sample that was sent to a lab to confirm the results from the rapid tests. The study was done between August 2020 and February 2022.
On average, participants were 32 years old and 85% were in a correctional facility.
Results
HIV
Both rapid tests identified HIV infection in 24 people. The tests had a sensitivity of 100%. Twenty of these people had been diagnosed previously. Among these 20, nine people were taking HIV treatment (ART). All 24 people were either re-linked or linked to clinics for ongoing HIV care.
Syphilis
Both rapid tests were highly sensitive (98%), with a total of 202 cases of infectious syphilis found. The vast majority of these cases were offered immediate treatment. The remaining participants were treated within four days of a positive test result.
Four people (less than 0.3%) had false positive rapid tests for syphilis. The researchers noted that “the benefits of immediate treatment [of syphilis] likely outweigh the risks,” particularly among people who may not return to get their test results (if such testing were done by a lab).
Bear in mind
- The study found that dual testing for syphilis and HIV was successfully integrated into different settings.
- Tests were administered by healthcare professionals.
- Test results were made available in less than five minutes.
- These rapid results meant that immediate treatment could be offered for syphilis, thereby dispensing with additional visits.
For the future
The results from the present study, along with other data, are being reviewed by Health Canada. If the rapid syphilis-HIV tests are approved by Health Canada, they hold the promise of making testing (and likely treatment) for these two STIs faster and more accessible.
Note that in the present study healthcare professionals administered the tests. The Alberta researchers are planning studies that would assess the administration of rapid STI test kits by peers or staff in community-based organizations. Also under consideration is a study to assess the potential of the kits to be used for self-testing.
—Sean R. Hosein
Resources
Syphilis – Government of Canada
Responding to Syphilis in Canada – Government of Canada
Congenital syphilis – National Collaborating Centre for Infectious Diseases
Syphilis – Government of Quebec
Syphilis outbreak – Alberta Health Services
Syphilis – British Columbia Centre for Disease Control
Global Health Sector Strategies – World Health Organization
Alberta study underscores the importance of syphilis testing in people who use stimulants – CATIE News
Alberta study finds high rates of sexually transmitted infections among people in prison – CATIE News
Study finds some people with HIV are at greater risk for STIs – CATIE News
A syphilis awareness and education campaign for men makes some progress in B.C. – CATIE News
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