One dose HPV vaccine offers ‘solid protection’ against cervical cancer, says WHO
Most commonly administered to girls aged 9-14, the vaccine protects against HPV, the virus that causes cervical cancer.
Cost-effective and easier to administer
HPV vaccines have been licensed for over decade: initially administered as a three dose schedule but reduced to a two dose schedule in 2014 for under 15s.
During its meeting this month, SAGE evaluated evidence that has been emerging over the past few years with regards to the efficacy of a one dose schedule: saying the one dose schedule has the potential to be a 'game-changer'.
The current WHO recommendations for HPV vaccination is two doses (0 and 6 months) for girls under 15 years old; and three doses (0, 2 and 6 months) for those over 15 years old.
For women aged 9 to 20 years old, SAGE now says countries may choose between a one or two dose schedule. A two dose schedule (0 and 6 months) is suggested for women older than 21.
Three HPV vaccines are marketed in many countries around the world: GSK’s bivalent Cervarix; Merck’s quadrivalent Gardasil and its nonavalent Gardasil 9.
All are ‘highly efficacious’ in preventing infection with virus types 16 & 18, which together are responsible for 70% of cervical cancer cases.
The quadrivalent vaccine also protects against anogenital warts, caused by infection with HPV types 6 & 11. The nonavalent vaccine provides additional protection against HPV types 31, 33, 45, 52 & 58.
China’s Innovax received WHO prequalification in October for its bivalent HPV vaccine Cecolin: noting supply of other HPV vaccines is insufficient to meet demand.
Immunocompromised individuals, including those with HIV, should receive three doses if feasible (and if not at least two doses) given the limited evidence regarding the efficacy of a single dose in this group, adds the SAGE committee.
More than 95% of cervical cancer is caused by sexually transmitted HPV, which is the fourth most common type of cancer in women globally with 90% of these women living in low- and middle-income countries.
In 2020, the Cervical Cancer Elimination Initiative was launched to address several challenges including inequity in vaccine access.
However, global uptake of the vaccine has been slow, says the WHO: with coverage in countries much lower than the 90% target (in 2020 global coverage with 2 doses was only 13%).
Several factors have influenced the slow uptake and low coverage of HPV vaccines including supply challenges, as well as the programmatic challenges and costs related to delivering a two regimen to older girls who are not typically part of childhood vaccination programs.
Added to this has been the relatively high cost of HPV vaccines, particularly for middle-income countries.
WHO Assistant Director-General Dr Princess Nothemba (Nono) Simelela said: “The option for a single dose of the vaccine is less costly, less resource intensive and easier to administer. It facilitates implementing catch-up campaigns for multiple age groups, reduces the challenges linked to tracing girls for their second dose and allows for financial and human resources to be redirected to other health priorities.”
Supply and manufacture
A shortage of HPV vaccines has been a challenge: but manufacturers have been increasing production and SAGE says that supply and the supplier base is improving in the 'short- and medium term'.
Last week, Merck (known as MSD outside the US and Canada) announced it has expanded its vaccines manufacturing facility located in Elkton, VA, completing the construction of 120,000 square feet and adding 150 new jobs at the site to further increase capacity and supply of its HPV vaccine.
It says it is prioritizing access in countries with a high burden of disease, including countries eligible for support from Gavi and UNICEF. It will provide 91.5 million doses of its HPV vaccines for use in Gavi-supported countries from 2021-2025, as well as offering additional doses beyond that agreement as needed.
“Increasing supply of our HPV vaccines is a top priority, and over the last several years we have steadily increased our manufacturing capacity in response to growing global demand,” said Jacks Lee, senior vice president, Merck Manufacturing. “Despite the pandemic, our teams have completed the building infrastructure expansion at our Elkton site ahead of schedule and we are excited to reach this important milestone.”
In 2019, Merck committed more than $1bn to expand production capacity at existing manufacturing facilities and build new facilities to address the unprecedented global demand for its HPV vaccines. Merck has expanded and maximized its existing facilities, nearly doubling supply of our HPV vaccines from 2017-2020. It expects supply of its HPV vaccines to double again between 2020-2023 as the company continues to expand capacity at existing facilities and as new facilities come online.
HPV vaccines reduce cervical cancer rates by 87%, according to a study based on England's vaccination program.
