Discussion
Choice of Pathogens
Mr. Vock advised us to focus only on developing tests for pathogens where screening is truly needed. According to him, HPV and Trichomoniasis are less relevant for screening. HPV, he explained, is not meaningful in this context because it cannot actually be treated. Trichomonas, on the other hand, does not require screening since it is only relevant in specific diagnostic situations.
By contrast, he emphasized that Chlamydia and Gonorrhea are very important, as there are still no validated self-tests for these infections in Switzerland. He argued that this is mainly because PCR cannot easily be adapted into a self-test format. He mentioned an Indian company that has developed a kind of mini-PCR machine that you have to plug in, designed for single use, but he doubted that such a device would be accepted socially.
He also stressed that Syphilis is very important. While rapid tests exist, he explained that they are not specific enough, with the main challenge being the quality of blood testing. Typically, either finger-prick blood or venous blood is collected and sent to a laboratory. He noted that HIV testing requires only a small amount of blood, making finger-prick sampling feasible. Syphilis testing, however, requires much more blood, so using a simple finger-prick is usually insufficient. Finger-prick sampling often produces too little blood for a reliable result. “For a proper test, you would almost need to cut off the finger, which of course is not an option,” he joked. He also noted that Roche is currently pushing an approach using dried blood, where a drop of blood is dried and then sent to a laboratory, but this is still in very early stages. According to him, this is the current testing field as it exists.
Regarding the self-test of AIDS Hilfe Schweiz
He noted that self-application was prohibited. There are numerous laws regarding medical devices, one of which states that a product must not be used outside of its intended purpose. For self-tests, the challenge is that untrained people perform the procedure. He explained that a costly study, usually performed in a foreign country, is required to show that laypeople can use the device safely, without risk of death or other potential harm.
For STI tests, sample collection can already be risky. For example, collecting a throat sample requires reaching far back, not just superficially. Usually, this is difficult for laypeople. A full test would require three samples: throat, anal, and genital (urethral/vaginal) swabs. He explained that while vaginal sampling can work, urethral sampling is difficult. There is no product approved for untrained people, so samples would need to be pooled with urine, which proved too expensive. Consequently, the company abandoned this approach.
He added that there might be exceptions in the future, similar to HIV and COVID tests. Otherwise, approval and certification are generally required. Certification is mandatory; without it, the product would be illegal. He emphasized that certification does not mean the product is necessarily good—it only ensures that it functions as described (e.g., meeting a claimed specificity of 50%), is safe, and complies with production standards.
Regarding performance expectations, he said that specificity in Western Europe is generally expected to be above 99%, because customers would otherwise not accept it, given that PCR is the standard. Sometimes, this level of specificity is even considered ‘too good’. For example, with Mycoplasma, this can be problematic because very minor infections are clinically irrelevant, but if tested, they will be detected by PCR in the same way as major infections.
He noted that regulations in Switzerland are generally aligned with those across Europe regarding approval and certification. They plan to implement their solution with a Dutch company, but only for home sampling, not home testing. Currently, HIV is the only reliable home test available in Switzerland. According to him, if we want to develop something that is truly needed, Syphilis would be the only viable option.
Regarding disease data and costs, including the long-term effects of undiagnosed STIs, he said he could not provide further guidance. He explained that this is very complex, unpublished for Switzerland, and that modeling it would essentially be a doctoral thesis. He suggested consulting the BAG Annual Report 2024.
General tips to conclude
He advised keeping the scope small, focusing on a single STI. For example, Syphilis requires measuring three values, and in the case of prior infection, pipetting techniques make it extremely complex. Chlamydia and Gonorrhea are different infections with very different needs and costs. He noted that even identifying health-specific data for one infection would surpass what BAG currently provides, due to the large number of cases and the frequent small costs, making it difficult to summarize them all (e.g., ten cases for each cancer type).
