Progress toward norovirus vaccines: considerations for further development and implementation in potential target populations

Abstract

Human norovirus infection causes significant medical and financial costs in the USA and abroad. Some populations, including young children, the elderly, and the immunocompromised, are at heightened risk of infection with this virus and subsequent complications, while others, such as healthcare workers and food handlers are at increased risk of transmitting it, and some are at risk of both. Human noroviruses are heterogeneous with new strains emerging periodically. In addition to viral diversity, incompletely understood characteristics, such as virus–host cell binding and duration of immunity after infection add to the challenges of creating a norovirus vaccine. Although much progress has been made in recent years, many questions remain to be answered. In this review, we discuss the important areas and relevant literature in considering human norovirus vaccine development and potential targets for implementation.

Keywords:

• calciviridae
• epidemiology
• gastroenteritis
• norovirus
• Norwalk agent
• vaccine development

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Human norovirus remains a significant clinical and economic burden globally.

• Several groups should be considered as potential targets for vaccination: children, the elderly, the immunocompromised, travelers, the military, food handlers and healthcare workers.

• Some groups at high risk for infection and clinical complications, some groups are at risk for transmission to others, and some are at risk for both.

• Data from current clinical trials of VLP-based vaccines show some promise with prevention of severe gastroenteritis among healthy subjects but similar data from some target populations, including children, the elderly, and the immunocompromised, are not available.

• Although GII.4 is most often implicated in endemic and outbreak settings, the role of non-GII.4 genotypes, and cross-protection between genotypes, need to be clarified among target populations.

• Observation and modeling studies have given estimates of duration of immunity to human norovirus ranging from 6 months to 8.7 years but further research is warranted to determine this among target groups.

• Refined estimates of cost–effectiveness based on actual vaccine performance are needed.

• Optimal timing and incorporation of a human norovirus vaccine into the current immunization schedule remains to be clarified.