Prompted by the life-saving impact of messenger ribonucleic acid (mRNA) vaccines during the COVID-19 pandemic, the World Health Organization's (WHO) Science Council has released a report reviewing the potential benefits and limitations of mRNA vaccine technology. The report conveys the importance of research and development (R&D) efforts to COVID-19 mRNA vaccines and outlines challenges of inequitable access.
The success of mRNA COVID-19 vaccines resulted from decades of investment in basic science exploring chemical modifications of – and immune responses to – RNA, with their potential applications for HIV, respiratory syncytial virus (RSV), severe acute respiratory syndrome (SARS), and cancer therapeutics and vaccines. Other key factors included thousands of people enthusiastically volunteering to participate in clinical trials, collaborations between researchers, and unprecedented levels of funding.
However, the benefits of the mRNA COVID-19 vaccines were not distributed equally globally, with insufficient research and development capacity, intellectual property barriers and ultra-cold-chain requirements as well as high costs for low- and middle-income countries.
"Unlocking the potential of mRNA technology beyond COVID-19 vaccines will require robust research to address limitations head-on," said Professor Harold Varmus, Chair of the WHO Science Council, a Nobel Laureate and former Director of the U.S. National Institutes of Health. "To improve mRNA vaccine technology, future research should seek to seek to develop more temperature-stable vaccines, increase how long protection lasts, and ensure effectiveness against a diverse range of strains and variants."
The report recommends a framework to assess the value of mRNA technology in developing vaccines and therapeutics against other infectious diseases. A framework could also help establish the technology's potential role in addressing cancer and autoimmune diseases.
To inform such a framework, the report maps out the clinical trial status of mRNA vaccines in the most advanced stages of development. While the COVID-19 vaccines are the only safe and efficacious preventive mRNA vaccines developed and approved for human use to date, mRNA vaccines against cytomegalovirus (a common virus that can threaten babies and those with a weakened immune system), influenza A and B, and RSV are in Phase 3 trials. There is also on-going discovery work in tuberculosis, malaria, HIV as well as noncommunicable diseases.
The report also calls for further research to address the potential of this technology as well as its limitations. Improving the stability of mRNA vaccines at higher temperatures should be a key target of investment and research efforts. Another key recommendation is ensuring end-to-end development and access by way of investment and applying lessons from COVID-19 initiatives, such as the ACT-Accelerator, which worked to secure access to COVID-19 tests, treatments, and vaccines.
"To maximise the impact of mRNA technologies, it's vital to promote and strengthen research, going country by country, so every region has a dynamic and sustained scientific, research and development ecosystem," said Dr Jeremy Farrar, WHO's Chief Scientist. "Coupled with investment and a commitment to equitable access, a more diverse global research ecosystem will better address communicable and noncommunicable diseases and improve health outcomes with new safe and effective mRNA vaccines and potentially therapeutics for all."
The report also underscores the importance of building trust, and improved communication around mRNA technologies to limit vaccine hesitancy and misinformation and improve current and future vaccine uptake.
