There are several possible scenarios for how the coronavirus pandemic will play out in the next few years, and each one that points to a return to normalcy, with the least number of lives lost, includes safe and effective vaccines. Not surprisingly, developing and deploying Covid-19 vaccines has been a major focus for governments and international organizations.
Even if this pandemic is not unprecedented—the 1918 influenza killed as many as 50 million people, and the HIV pandemic remains a public health problem—it is one of the most significant global emergencies the world has faced in a long time. But major crises can be a useful opportunity to build efficiencies into global systems. If there is a ray of light, it is that the experience of developing a rapid vaccine for the coronavirus could also reform and improve the global system for the creation and distribution of vaccines for other diseases in the future.
There are several coronavirus vaccines in development. Currently, at least 145 vaccine programs have been announced—with more than 10 vaccines already in human clinical trials. Many experts predict that a licensed vaccine will be available in 10 to 16 months. But substantial uncertainty remains. The wide range of timelines is at least partially due to the vaccine development process: A lot of things need to go right for a vaccine to be available in a timely manner.
Vaccine development often starts with identifying an antigenic target—the part of the pathogen against which an immune response is likely to provide protection from infection (or against disease even if infection is not prevented). This is usually followed by animal studies to examine and test features of potential vaccines. A candidate vaccine is then developed for human trials. Conventionally, human trials are divided into Phase I, II, and III trials for pre-licensure evaluation of vaccines. In Phase I trials, which usually include only a small number of people, the main objective is to evaluate safety while measuring immune responses (although the sample size is rarely adequate for proper evaluation of vaccine immune responses). Phase II trials can include a few dozen to a few hundred people and focus on immunogenicity—whether the body mounts adequate immune responses. Phase III trials usually include thousands of people and detect the efficacy of the vaccine in preventing the infection or disease. Both Phase II and III trials continue to monitor vaccine safety.
If everything goes right and a vaccine candidate meets the benchmarks for success and safety, regulatory agencies such as the U.S. Food and Drug Administration and the European Medicines Agency grant licensure. This is usually followed by public health and clinical recommendations by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices and similar entities in other countries. The vaccine is then incorporated into immunization programs. Vaccine research does not stop at licensure. For example, Phase IV studies (often labeled as Phase IV trials—even though most of them are observational studies) evaluate the real-world effectiveness of vaccines after they are introduced into the population. These post-marketing studies also evaluate the safety of vaccines for outcomes that are too rare to be identified in pre-licensure studies.
With the race to develop a coronavirus vaccine, there are efforts to speed up the vaccine development process. The progress so far has been encouraging. The expediency in the vaccine development process has mostly been due to implementation of several steps in parallel. For example, a few vaccine development plans include conducting Phase I and II trials together, and vaccine candidates similar to ones already used in humans are being evaluated simultaneously in human trials and animal models. Notably, so far, the increase in the speed of the development of vaccines comes through implementing efficiencies in the process—not by skipping critical steps.
Whenever the world gets a coronavirus vaccine, the lessons from the hunt for this vaccine are likely to change the development and deployment process of vaccinations.
Efficiencies identified today are likely to inform the development plans for future vaccines. Innovative trial designs and parallel conduct of human and animal studies are here to stay. The new categories of vaccines being evaluated, such as messenger RNA-based vaccines—which use transcripts of viral genes to induce our own cells to produce proteins to precisely stimulate the immune system against the virus—are likely to be retooled for other infections in the future. The speed with which the virus sequence was publicly shared and used for developing vaccine candidates will serve as a model for new outbreaks of disease in the years ahead.
The changes in the vaccine ecosystem will also include how vaccine development programs are managed. After the 2014 West Africa Ebola outbreak, global vaccine and public health leaders came together to establish a public-private partnership called the Coalition for Epidemic Preparedness Innovations (CEPI), which focuses on speeding up vaccine development for emerging infectious diseases. CEPI has already provided funding for nine candidate vaccines—the highest by any single entity.
CEPI is funded by governments as diverse as the United Kingdom and Ethiopia and private foundations such as the Wellcome Trust and the Bill & Melinda Gates Foundation. The U.S. government, on the other hand, has decided not to provide any funding to CEPI. Given that vaccine development and trials are an increasingly multicountry exercise, investing in multiple vaccine candidates increases the chances that at least one of them will be successful in gaining licensure and be available for vaccinating the U.S. population (and people in other countries).
The other major global vaccine entity is Gavi—an alliance responsible for making vaccines available to people in low-income countries. Unlike CEPI, Gavi counts the U.S. government among its financial supporters. Gavi's current portfolio mostly includes routine vaccines for children and adolescents. In this pandemic, Gavi is likely to expand its role to support pandemic vaccines for adults as well as children.
Another likely legacy of the coronavirus crisis could be a global adult vaccination program. The early priority groups for a Covid-19 vaccine are likely to include the elderly, health care workers, and people with co-morbid conditions such as hypertension—mostly adults. Globally, very few countries routinely immunize adults, and those that do have a low vaccination rate for adults. For Covid-19, return to normalcy will only be possible if a high enough population—including adults—are vaccinated, inducing herd immunity. To do so, the world will have to develop and expand adult immunization systems. Such a system is likely to outlast the pandemic phase of Covid-19 and will be useful for increasing the availability and coverage of other adult vaccines such as those against influenza and pneumonia.
While the many adaptations in the vaccine development and deployment process forced by the coronavirus outbreak are likely to outlast the pandemic, a resilient and innovative vaccine system will require going beyond what is being tried. For example, many had the naive belief that, given Covid-19's toll, there will be universal acceptance of a vaccine against it. While a coronavirus vaccine is yet to be deployed, survey data indicates that a substantial proportion of Americans might refuse the vaccine.
"Plandemic," a 26-minute viral video propagating outlandish conspiracy theories about Covid-19, vaccines, and Bill Gates—a prominent vaccine proponent—garnered millions of views in only a few weeks. There's no coherent large-scale response to vaccine-related misinformation and emerging mistrust in Covid-19 vaccines. A lesson from this pandemic is to expect and prepare for countering misinformation early in a pandemic.
Assuring safety of novel vaccines is at the core of science-based vaccine development. Fast, large-scale deployment of a pandemic vaccine requires systems to rapidly detect and evaluate safety signals. Missing a real safety signal or not being able to rapidly rebut a false signal can seriously undermine a vaccine program. Assessing vaccine safety requires large databases and monitoring systems—particularly to detect rare but important vaccine side effects. Currently, many countries have data systems for monitoring vaccine safety, but these systems are usually siloed, and efforts to connect them have been met with technological and bureaucratic challenges. Going forward, it will be essential to connect these systems to conduct large, multicountry studies of rare side effects.
Major crises often perturb the status quo. This is no different for the Covid-19 pandemic and its impact on the global vaccine ecosystem. If managed well, the changes underway to address the Covid-19 pandemic can help modernize vaccine development and deployment for all diseases.
Saad B Omer, is the director of the Yale Institute for Global Health. Twitter: @SaadOmer3
Disclaimer: This article first appeared on Foreign Policy, and is published by special syndication arrangement