
A meta-analysis of 31 studies suggests high rates of cervical infections with non-vaccine, high-risk human papillomavirus (HR-HPV) in women, regardless of vaccination status.
For the analysis, published last week in BMC Infectious Diseases, researchers in Brazil included observational studies that assessed the prevalence of cervical infection by HR-HPV type among vaccinated and unvaccinated women and were published up to July 14, 2023.
Worldwide, HPV is the most common sexually transmitted infection of the lower genital tract and the main cause of cervical cancer, the authors noted. It is also the fourth most common disease in women globally and the leading cause of death in 42 countries.
Three HPV vaccines have been licensed: bivalent (two-strain [2vHPV]), which targets HPV types 16/18 (Cervarix); quadrivalent (four-strain [4vHPV]), which targets types 6/11/16/18 (Gardasil); and nonavalent (nine-strain), which targets types 6/11/16/18/31/33/45/52/58 (Gardasil-9).
Rates for some types lower in vaccinated women
Among the 59,035 women included in the analysis, 42% had received at least one dose of HPV vaccine. Of the 31 studies, 64.5% used 4vHPV, 32.3% used 2vHPV, and 3.2% used both.
Further studies with vaccinated women are needed to understand the effects of vaccines on the distribution of non-vaccine HR-HPV types.
There was a high prevalence of non-vaccine HR-HPV types 31/33/45 (prevalence ratio [PR], 0.60), 31 (PR, 0.47), and 45 (PR, 0.38). While prevalence was high regardless of vaccination status, the rates of types 31/33/45, 47, and 45 were lower in vaccinated women, which the authors said suggests that the vaccines offer some cross-protection against these types.
"Further studies with vaccinated women are needed to understand the effects of vaccines on the distribution of non-vaccine HR-HPV types," the study authors concluded.