Researchers conducted a randomized controlled trial in Tanzania to see how malaria affects the effectiveness of HPV vaccines. The study included 930 HIV-negative schoolgirls between the ages of 9 and 14. They looked at girls receiving either one or two doses of the Cervarix or Gardasil vaccines while testing for the presence of malaria.
For girls who received only one dose of the vaccine, the researchers found no difference in antibody levels regardless of whether they had malaria. However, for those receiving two doses, the results were different. In the two-dose Cervarix group, girls with malaria had lower antibody levels for both HPV16 and the avidity index. Similarly, in the two-dose Gardasil group, girls with malaria at the first dose had lower antibody levels for HPV18.
While these differences were observed in the two-dose groups, the researchers noted that the changes were small in magnitude. They suggested these findings are unlikely to have a major impact on clinical outcomes. Because the study is limited by not knowing the impact of high parasite loads, these results should be viewed as a specific finding regarding antibody levels rather than a change in overall vaccine effectiveness.
