Editor’s Note: This is the 96th in a series on optimal diet and lifestyle to help prevent and treat disease. Any planned change in diet, exercise or treatment should be discussed with and approved by your personal physician before implementation. The help of a registered dietitian in the implementation of dietary changes is strongly recommended.

Transitioning from a Lifestyle Approach to a Vaccine for Covid-19

By Paul E. Lemanski, MD, MS, FACP

While a lifestyle approach to Covid-19 provides the foundation for the current strategy to mitigate the risk of the virus, how it dovetails with and transitions to a vaccine is important. In my last two articles on Covid-19 (June and August 2020), I argued for a more “balanced” approach. 

As with most lifestyle-based recommendations, you begin with near universal masking, in addition to social distancing, handwashing, targeted quarantine and contact tracing. The approach suggested may be described as more “balanced” because the implementation relies on risk-stratifying the population, reserving more aggressive and socially disruptive interventions such as targeted lockdowns, extensive testing, and stay-at-home orders only for those older and sicker individuals at higher risk. 

The majority of the population at lower risk would rely on proven lifestyle-based risk mitigation strategies to keep the rate of new infections low. Such a low rate of infection would allow the economy to reopen, children to return to school, and Americans to return to a more normal life. I emphasized that such an approach would only work if the great majority of folks actually implemented such mitigation strategies. Thankfully, in some areas of the country, including New York State, the rate of infection is now low enough to further protect the health and well-being of our population by reopening the economy and reopening our schools.

The present article will address the transitioning from this lifestyle-based approach to a vaccine and an immunological broad-based protection of our population. Protection of the population, especially those at higher risk, cannot involve actually physically isolating these folks forever. It must involve immunological isolation or what has been referred to as “herd immunity.” Essentially, the concept of herd immunity is that if I am at risk – with no immunological antibody protection from the virus – I need to surround myself with individuals (the so called “herd”) who are immune to Covid-19, because either they have antibodies from a natural infection from which they have recovered or antibodies from a vaccine. If I am surrounded by such a herd, I do not need to have antibodies myself to avoid an infection. I am protected by the herd.

Typically, approximately 60-70% of a population needs antibodies to a virus – again, either by natural infection or vaccine – to achieve herd immunity. The percentage of the population needing antibodies depends on the ease of contracting an infection from another individual. It also assumes no other natural protection from infection and a random exposure to infected individuals. Yet, with Covid-19 we suspect some individuals may have partial protection from prior exposure to other coronaviruses, or a genetic resistance to infection. It is also clear that individuals are not exposed to other individuals randomly, but by age and social groupings. This has led some researchers to model lower rates of infection perhaps as low as 20-40% to achieve herd immunity.

Additionally, such modeling assumes long term immunological protection, in which infected individuals who recover and vaccinated individuals, maintain their antibodies long-term. If antibodies are not long-term, then achieving herd immunity becomes more difficult.

If such lower rates of infection achieve immunological protection of our population, then we may be approaching a tipping point in the pandemic. Younger individuals placing themselves at risk and becoming infected and recovering will – after recovery – actually protect those at higher risk. Higher risk individuals will need to maintain the lifestyle-based mitigation strategies outlined above until a vaccine – proven to work – is available. The CDC is suggesting that once a vaccine – proven to be safe and effective – is available first-responders and those at highest risk will be offered the vaccine first. Even so, the logistics of producing a vaccine in sufficient quantity and immunizing even 50% of the population at risk will be daunting.

Thus, the strategy of risk stratifying the population and allowing younger, otherwise healthy, lower risk individuals to develop antibodies in the process of returning to a more normal life – while still encouraging lifestyle-based risk mitigation strategies – makes some sense. Such an approach would help avoid the significant harm to the health of the population from draconian economic restrictions and at the same time present a way to more rapidly achieve herd immunity, pending a widely available vaccine.

One final word on vaccines: we all want a vaccine that is safe and effective, but we also need one sooner rather than later. I am a strong proponent of challenge trials as opposed to over-reliance on randomized, placebo-controlled trials, when the risk to our population’s health and national economy is severe. The gold standard of medical research is the randomized, placebo-controlled trial. A group of individuals is chosen randomly to receive either the test vaccine or a placebo vaccine. The two groups are then followed over time, and the rate of infection of each group, on routine daily exposure to the virus that we all experience in the course of our lives is measured. If the natural presence of the virus is low as in New York it may take a while to see a difference between the test vaccine and placebo groups. 

A challenge trial involves taking a group of volunteers, at first in low-risk groups, inoculating them with the test vaccine and then challenging them (thus the name) with an on-purpose exposure to Covid-19 from a culture of the virus. A challenge trial has the risk of on-purpose exposure. However, by choosing those at lower risk first, researchers would know within several weeks if a vaccine was effective. If the outcomes are acceptable, higher risk groups could be tested. Moreover, the risk may be mitigated by closely following those exposed to the virus and intervening early with available treatment. I would suggest that both challenge trials and randomized, placebo-controlled trials should not only be used aggressively, but also promoted to the public and vetted in public discourse by ethicists and those on institutional review boards for research with human subjects.

In summary, in my opinion, a successful approach to Covid-19 requires the use of proven lifestyle-based mitigation strategies including near universal masking, social distancing, handwashing, targeted quarantine and contact tracing. In addition, a balanced strategy of risk stratifying our population, reserving the most aggressive interventions for those at highest risk and allowing those at lowest risk to return to work, and school is essential to protecting the overall health of our population. Vaccine development may be accelerated by the use of challenge trials, which should be explained to the public by medical professionals specializing in ethics and developed and vetted with the input of institutional review boards. 

Using such an aggressive, coordinated approach may allow herd immunity to be achieved more quickly with the minimum loss of life, while avoiding an economic collapse, and the risk to the health of the nation such a calamity could engender.

Paul E. Lemanski, MD, MS, FACP is a board-certified internist practicing internal medicine and lifestyle medicine in Albany (centerforpreventivemedicine.com). Paul has a master’s degree in human nutrition, he’s an assistant clinical professor of medicine at Albany Medical College, and a fellow of the American College of Physicians.