One instead of three
Clinical trials have shown the effectiveness of a single dose of HPV vaccine
Peter Kazimirov, PCR.news
Clinical trials have been conducted in Kenya, which demonstrated that a single administration of a bi- or nonavalent (against nine strains) vaccine against human papillomavirus provides protection against carcinogenic strains 16 and 18 at the level of 97.5%. Currently, vaccination with three doses is recommended, and the revision of this recommendation, according to the authors, will help increase the coverage of the population.
More than 90% of new cases of cervical cancer in 2020 were in low- and middle-income countries. The main method of combating this type of cancer is vaccination against human papillomavirus (HPV), the main cause of the disease. However, in low-income countries, it is extremely difficult to ensure the necessary coverage of the population. One of the difficulties is the need for revaccination. For example, in Kenya, only a third of children received a second dose of the vaccine. Clinical trials conducted in Kenya have shown the effectiveness of a single dose of the vaccine.
The clinical trials involved 2,275 women aged 15-20 years. They were randomly divided into three groups — 758 received one dose of nonavalent vaccine (effective against HPV strains 16/18/31/33/45/52/58/6/11); 760 received one dose of bivalent vaccine (effective against the main carcinogenic HPV strains 16/18); 757 received meningococcal vaccine, which was used as a control.
Swabs from the cervix and vagina were taken from the patients, the latter 18 months after vaccination. For various reasons, some participants were excluded from the trial.
When analyzing strains 16 and 18, 38 cases of infection were detected: one each in the first two groups and 36 in the control group. The effectiveness of both HPV vaccines was 97.5%. When analyzing strains 16/18/31/33/45/52/58, 33 cases of infection were detected: four in the group that received the nonavalent vaccine and 29 in the corresponding control group. Taking into account all factors, the effectiveness of the nonavalent vaccine in this case was 88.9%.
Thus, scientists have shown the effectiveness of using a single dose of HPV vaccine. They believe that amendments to the recommendations on vaccination will help increase the availability of vaccines for the population and reduce the cost of the project.
Barnabas at al. Efficacy of Single-Dose Human Papillomavirus Vaccination among Young African Women is published in the journal NEJM Evidence.
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