Accelerating access to current and future rotavirus vaccines

Unlike other forms of diarrhea, rotavirus cannot be prevented by improvements in water quality, hygiene, and sanitation. Because of this, vaccination is the most effective way to protect children from rotavirus. Rotavirus vaccines have made a tremendous impact in the 120+ countries where they’ve been introduced, but many children around the world remain unprotected, especially in Southeast Asia.

Accelerating introduction

We could accelerate access by homing in on the Valeriepieris circle—a region with a radius of four thousand kilometers in Asia that includes approximately half the world’s population. By focusing on Gavi-eligible countries within this region that are planning to introduce the rotavirus vaccine, such as Bangladesh, Cambodia, Laos, and North Korea, we could maximize impact by reaching a significant number of unvaccinated children.

The Valeriepieris circle. Credit: Wikipedia

Since Gavi typically supports vaccine introduction efforts in low-income countries based on national income, it is strategic for countries like Bangladesh to expedite the introduction process before they become ineligible for this kind of support. Time is of the essence.

Investing in research

There are four rotavirus vaccines prequalified by the World Health Organization (WHO). Infants can begin receiving these vaccines at 6 weeks old and should complete the series by the time they are 8 months old. The vaccines can be co-administered with other parenteral routine vaccinations without any interference.

In parallel to reaching as many children as possible with the current vaccines, researchers are exploring next-generation vaccines that solve persistent challenges. One area of inquiry is to explore how vaccines can maintain strong efficacy in children who are malnourished or have gut damage. For this reason, research on injectable (as opposed to oral) vaccines is underway.

Injectable rotavirus vaccines pose a different set of challenges. Development requires a careful balance between immunogenicity—the vaccine’s ability to induce a strong immune response across multiple rotavirus strains—and the preservatives that maintain the vaccine’s integrity and shelf life. Some preservatives may weaken immune responses, making this balance crucial for the vaccine’s overall efficacy.

Once a viable candidate is available, combining injectable rotavirus vaccines with the DTP-pentavalent vaccine—which protects against diphtheria, tetanus, pertussis, Haemophilus influenzae type b, and hepatitis B—has the potential to dominate the rotavirus market in Gavi-eligible countries as well as in non-Gavi middle-income countries, with availability projected by 2027. This would provide a welcome addition to the available product options, but would not supplant the ongoing need for existing oral rotavirus vaccines.

Integrated approach

Vaccines are imperative for driving down the burden of rotavirus in low-income countries where the disease burden is still substantial. But it remains only one piece of the puzzle to control diarrheal disease with proven preventive measures, such as improved hygiene and sanitation, handwashing with soap, exclusive breastfeeding for the first 6 months (which can enhance vaccine-induced immunity), and proper infant nutrition. Additionally, effective treatment strategies like oral rehydration solution and zinc supplements are essential. By integrating these solutions, we can help ensure that children are protected against rotavirus and other forms of diarrheal disease.

Cover photo: A mother and child participate in a Phase 1 Shigella vaccine trial in Dhaka, Bangladesh. Credit: PATH.