In response to the SARS-CoV-2 pandemic, we are currently witnessing the fastest vaccine development in history. While these vaccines will now make a significant impact on ending the pandemic, they were needed much earlier. Here I discuss how to ensure that vaccines will become available within 3-4 months after a new outbreak.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in late 2019 in Wuhan, China, and caused a global coronavirus disease 2019 (COVID-19) pandemic.
Since then more than one million people have died globally, millions have been infected, and in many countries we are seeing signs of societal disintegration. The global economy has taken a major hit and businesses in many areas including tourism, hospitality, and the airline industry are fighting for their survival or have already gone bankrupt. Daily life has become difficult, even for people who have not been infected or have lost loved ones. In addition, while countermeasures like social distancing, wearing face masks, and restrictions on large gatherings (especially indoors) can help to keep infections low if effectively implemented, the populations in many countries are getting tired and are often unwilling to comply to countermeasures, let alone complete lockdowns.
Vaccines against infectious diseases have been one of the greatest successes in human history, effectively reducing disease burden for many pathogens. They have even allowed us to eliminate a human virus (smallpox) and a livestock virus (Rinderpest virus) from the face of the earth. When the sequence of SARS-CoV-2 was made openly available by Chinese scientist on January 10, 2020, a race to develop a vaccine began.
This was not a race of vaccine candidates against each other, but a race against the virus. SARS-CoV-2 vaccine development is moving ahead at record speed. Based on important development work already done on other coronaviruses,
the first individuals were enrolled in phase 3 trials in summer 2020, and results showing high effectiveness of two of these vaccines were recently reported. This speed of vaccine development is unprecedented, and the vaccines will likely be key in ultimately resolving this situation. They will also save millions of lives. However, vaccines were needed much earlier, as early as possible (Figure 1A). While it is unlikely that vaccines would have stopped the virus from going global, a well-prepared infrastructure capable of producing vaccines 3–4 months into the outbreak (in March or April) would have saved many lives and would likely have normalized the situation in many geographic areas by now (Figure 1B). Still, without vaccines, countries in the Northern hemisphere experience a strong increase in cases during the fall, even in countries that controlled the initial wave well. Here, I will try to provide a strategy that might allow us to be better prepared in the future from a vaccine perspective.
Figure 1Overview of the Current Situation with SARS-CoV-2 and an Ideal Scenario from the Vaccinology Point of View
Many different viruses may cause a pandemic in the future, but we know which virus families have the most potential. And it is viruses that spread from human to human via the respiratory tract that we worry about the most, since this is a transmission route that is hard to stop. Viruses that use other transmission routes can be highly problematic as well but might be impacted much more by non-pharmaceutical interventions. From each of the identified virus families, which should certainly include the Paramyxoviridae, Orthomyxoviridae, and Coronaviridae families, a handful of representative strains with the highest pandemic potential should be selected for vaccine production. Up to 50–100 different viruses could be selected and this would broadly cover all phylogenies that may give rise to pandemic strains. Importantly, the more we know about viruses circulating in animals and their pathogenicity, the easier it will be to choose relevant strains (Figure 2). If this sounds farfetched, we should consider that the number “2” in SARS-CoV-2 indicates that this virus is genetically related to SARS-CoV-1, the virus responsible for the SARS outbreak in 2003.
It should be possible to choose candidates that are close to viruses that might emerge in the human population. The idea is that once viruses are selected, vaccines can be produced in different platforms and tested in phase 1 and phase 2 trials with some of the produced vaccine being stockpiled. This would likely cost 20–30 million US dollars per vaccine candidate resulting in a cost of 1–3 billion US dollars. In parallel, correlates of protection for related human viruses can be investigated (e.g., for human coronaviruses in the case of Coronaviridae). Production capacity can be built to allow rapid production of at least 2 billion doses per year using different vaccine platforms. If a new virus hits, the vaccine closest to the new strain is selected, a strain change is performed, vaccine production starts immediately, and phase 3 trials are initiated within a month. First readouts from the phase 3 trials would be expected likely post-second vaccination, and the vaccine could receive an emergency use authorization based on a correlate of protection 2 months after initiation of the trial. While initial trials continue, vaccine rollout is initiated, and production is ramped up.
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