Single-dose HPV vaccine can achieve immunity similar to 2 doses: Study

Single-dose HPV vaccine could provide similar immunity as two doses, easing burden on vaccination programs in countries like India with high cervical cancer rates.

A single HPV (human papilloma virus) vaccine dose can achieve an immune response similar to two doses, according to a recent research-based opinion put forth in The Lancet Infectious Diseases -- a finding that could ease the overall burden on the anti-HPV vaccination programme in a developing country such as India that has high cervical cancer burden.

According to government estimates, worldwide, cervical cancer is the fourth most common cancer in women. In India, it is the second most common cancer among women after breast cancer. (Representational image)

HPV, or human papillomavirus, is a common virus that can cause cancers later in life. According to government estimates, worldwide, cervical cancer is the fourth most common cancer in women. In India, it is the second most common cancer among women after breast cancer.

“…authors detail how a single-dose human papillomavirus (HPV) vaccine strategy advances vaccine equity, health equity, and gender equity. Recent research suggests that a single HPV vaccine dose can achieve an immune response similar to two doses. The authors argue that in addition to being effective at protecting against HPV for females and males, a single-dose strategy can ease pressure on vaccine supply, lower program costs, and is easier to distribute, reducing many current barriers to HPV vaccination, especially for hard-to-reach populations,” the Lancet article said.

Low-middle income countries such as India account for nearly 80% of the disease burden. In India, there are approximately 127,526 new cases and 79,906 deaths per annum, as per the GLOBOCAN 2022 data.

Most HPV infections— 9 out of 10— go away by themselves within two years. But sometimes, HPV infections will last longer and can cause some cancers. Among the cancers that HPV infections can cause are those of the cervix, vagina, and vulva. In India, about 5% of women in the general population are estimated to harbour cervical HPV-16/18 infection at a given time, and 83.2% of invasive cervical cancers are attributed to HPVs 16 or 18, according to India chapter of International Agency for Research on Cancer fact-sheet 2023.

HPV vaccination is meant to prevent cancer-causing infections and pre-cancers. Normally, a two-dose vaccine is advised but there is growing evidence that even single dose can offer similar protection. While the Indian government screens women for cervical cancer under its universal screening programme for non-communicable diseases, there are also plans to introduce vaccination against HPV under the national immunisation programme. This, however, is still under consideration.

“There has been no final decision in this regard yet by the health ministry,” an official familiar with the matter said, requesting anonymity.

Although many countries have recently adopted a single-dose HPV vaccine strategy, others continue with two-doses in their HPV vaccine programmes , putting pressure on resources and creating barriers to access for those most in need, according to the researchers in the article.

“There are ethical reasons to transition to a single-dose strategy... This change facilitates vaccine procurement and implementation programmes (contributing to vaccine equity) and reaching hard to reach people or populations (contributing to health equity). A lower number of cases of HPV-related diseases that stem from greater vaccine distribution reduces the burden on women, who are at a higher risk of HPV-related disease or who act as caregivers, which prevents them from accessing opportunities that contribute to their empowerment (contributing to gender equity). Thus, pursuing the single-dose HPV vaccination programme strategy is ethically desirable,” argue the authors.