Pandemic Policy in the Vaccine Era: The Long Haul Approach

The approved COVID-19 vaccines demonstrate a significant milestone in the pandemic fight, because their high rates of efficacy in clinical trials are now being borne out as improved health outcomes following vaccine distribution in those countries with significant rollouts. Vaccine development represents an international synergy of scientific discovery and technological achievement, reflecting collaboration among scientists, governments, big and small pharma, nongovernmental organizations, and the public, notwithstanding intense internal political struggles and pressures. The heroic efforts of the commons—notably, citizens from the agricultural, food transportation, education, waste management, medical, and other sectors—have filled the gap while public health measures have been implemented. However, the public, including researchers, health workers, policymakers, and the global citizenry, need to be reminded that, although one cannot minimize the importance of vaccine development, there are significant challenges ahead, both COVID-19 and non-COVID-19 related. These challenges are intimately tied to the fact that the SARS-CoV-2 is a pathogen with the ability to evolve in a complex ecological landscape: within infected individuals, across diseased populations, and possibly across animal reservoirs, resulting in novel variants with increased transmissibility and possibly higher virulence. Furthermore, the variety of public health measures, social behaviors at local and national levels, demographic profiles, and the underlying medical conditions of individuals among regions, the vaccination rates per capita, and the vaccine formulations themselves contribute to this ecological complexity. Below, we briefly highlight the challenges to minimize the health risks of COVID-19 and the policies that need to be implemented, reflecting generations of basic research in the biodiversity sciences, to safeguard the global human population.

Although there are potentially many obstacles ahead, there is good news. First, the recognition that human health is a consequence of human ecology is not a new concept, meaning we are closer to implementing safeguards than discovering what those safeguards are (e.g., One Health framework; Henley 2020). Second, vaccines are generally highly effective, and, compared with drug treatments, the evolution of viruses to bypass the induced immune response is rare, with the notable exception of the influenza virus (Kennedy and Read 2017). The inability of many viruses to evolve resistance to vaccines is grounded in evolutionary and ecological principles. Vaccines (as a prophylactic versus drugs as a therapeutic) prevent infection, often act on many variants, and elicit a general immune response that simultaneously acts against many characteristics of the target pathogen. Consequently, the reduced virus population size reduces the likelihood of selectively favorable mutations appearing in contemporary or future viral genotypes, producing the conditions that make it extremely difficult for the virus to simultaneously evolve to the multiple selective challenges posed by the immune response. However, given the great human and economic costs of this pandemic, we should be on guard to the outcome that current vaccines may be only a short-term solution to the pandemic challenge and that there remains a high probability for novel emerging pathogens to threaten global health in the future. Current evidence shows that the virus is experiencing intense selection for increased transmissibility, which is expected for an infectious pathogen emerging in a new host population containing highly abundant susceptible individuals. These ecological and evolutionary responses could lead to continued immense human suffering and loss, especially if we do not reach herd immunity. Even if vaccines with high efficacy are continually available, their ability to completely eliminate serious health challenges or death is paramount; otherwise, even in the United States, millions of people will suffer from SARS-CoV-2 infections, given that mortality is approximately five times higher than that of seasonal influenza for older, hospitalized patients, and there is increasing evidence that a significant number of patients with and without initial COVID-19 symptoms develop long-term health consequences. Consequently, we must remain vigilant, because the availability of effective vaccines is only the first step in a long journey that requires broad willingness to participate in the vaccination program, proper messaging on the role and value of science in addressing such massive global health threats, and the absolutely essential need to defend the integrity of science from mis- and disinformation programs.

We suggest some commonsense short- and long-term policy directed toward the research community in order to address the aforementioned existential challenges to human health and the social fabric. From both theoretical and empirical research in ecology and evolutionary biology, we know that transmissibility and virulence can be positively correlated, although there is no evidence of this occurring in SARS-CoV-2. Importantly, selection for higher virulence may be negligible, given that the virus is effectively transmitted by asymptomatic hosts (Day et al. 2020). Therefore, public health policy to reduce transmission rates will not only immediately reduce risks to the public but, in the long term, could also reduce the probability of viruses evolving to become more highly transmissible and possibly virulent. Because human travel is so prevalent, any policy to reduce transmission rates must consider the global population; otherwise, the COVID-19 spread will only be delayed and not prevented. Therefore, a robust system is needed to assess SARS-CoV-2 variants, their potential for increased transmission, and most important, their potential to evolve to overcome the immune response induced by the current vaccines (NASEM 2020a). Kennedy and Read (2020) proposed three sensible approaches to detecting potential evolution toward vaccine-induced immunities: vaccines targeting many and different epitopes, continued surveillance of the evolution of increased transmission rates associated with the evolution of new variants, and early detection of vaccine driven evolution of SARS-CoV-2, perhaps through a comparison of viral genotypes from vaccinated and unvaccinated groups. The latter two approaches are directly related to commonly used evolutionary approaches. Thankfully, the mRNA technology used in developing some of the approved vaccines facilitates the ability to tweak these vaccines rapidly, serving as a bulwark against new variants.

We also know from many decades of study that human population growth can lead to both reduced and fragmented natural landscapes, increasing the likelihood of zoonotic emergence of current and novel disease agents in humans. Therefore, there is a need for improved public understanding of virus transmission, increased virulence, and an understanding of how human population growth, shrinking natural habitats, and greater encroachment by humans into natural areas have exacerbated public health issues by increasing the opportunities for viral spillover from animals to humans. Compared with the economic costs incurred through the COVID-19 pandemic, the costs of implementing sound conservation policy to minimize the above factors are small (Dobson et al. 2020). Although conservation is always easier than habitat restoration, new strategies and techniques to elevate the role of sustainable and regenerative agriculture may contribute toward restoring the natural balance to the planet.

Although we can prioritize the importance of the natural landscape and biodiversity, it also behooves us to prepare an inventory of possible disease transfer by using an extended specimen approach, as was outlined in the Extended Specimen Network report from the Biodiversity Collections Network (Ledemer et al. 2019, NASEM 2020b). This approach supplements traditional data archiving of natural history specimens with enriched geospatial information and data on species interactions, including pathogens carried by the specimen of interest, and links to all other relevant data, such as DNA sequences on GenBank. From this extended data set, researchers can assess the likelihood of cross-species transmission to humans and compile the understanding necessary for quick, preemptive health policy to address the possible future concern.

Because transmission spread depends so much on human practice, a parallel priority should be to understand the social features that either promote or inhibit the use of nonpharmaceutical interventions such as mask wearing. We suggest a data-driven, high-throughput, convergent-science approach to evaluate factors affecting acceptance of science-based recommendations, to increase our understanding of the barriers to accept policies related to the common good. Findings from these types of studies may potentially inform how we deliver policies to the public—by appealing to our health and prosperity—on other crucial topics, such as climate change and conservation.

We emphasize the need for significantly increasing federal investments in basic and foundational research. Decades of curiosity-driven research paved the way for COVID-19 vaccines to be developed in record speed. We also draw attention and reiterate that methods borrowed from evolutionary and ecological disciplines are being used to formulate a robust public health response to the COVID-19 pandemic. These approaches include tracking the spread and evolution of SARS-CoV-2 from its origin in different species to spread among humans (phylogenetic approaches), modeling the spread of the virus among human populations (ecological and epidemiological approaches), discriminating between neutral and selective processes governing the spread of variants (core principles of evolution and population genetics), and the necessity to consider anthropogenic impacts on the environment that elevate the risk of introduction of novel human pathogens (biodiversity research including conservation biology and global climate change sciences).

Science has made great strides against one of humanity's most acute threats, with the achievement measured in lives saved. The challenge now is to redouble our efforts, building on our successes and bringing the same vigilance and force of effort to addressing the continued threat of COVID-19 and future novel pathogens. Given the existential challenge of human-induced climate change, our science and national policies need to reflect the nexus of risks that arise from biodiversity loss, stress to existing populations, and the loss of ecosystem services. Our response to COVID-19, and previous environmental risks such as the misuse of DDT, acid rain, and the depletion of the ozone layer, demonstrate that we have the capacity to address the global challenges threatening our health and prosperity and the time is now.

Acknowledgments

Scott Glisson, Sarah Otto, Jyotsna Pandey, and James Verdier provided helpful comments on a draft of the manuscript.

Author Biographical

Charles B. Fenster (charles.fenster@sdstate.edu) is the director of the Oak Lake Field Station, at South Dakota State University, in Brookings, South Dakota, in the United States. Pamela S. Soltis is affiliated with the Florida Museum of Natural History and with the Biodiversity Institute, at the University of Florida, in Gainesville, Florida, in the United States. Paul E. Turner is affiliated with the Department of Ecology and Evolutionary Biology at Yale University and with the Program in Microbiology at the Yale School of Medicine, in New Haven, Connecticut, in the United States.

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