There are multiple COVID-19 vaccines. What’s next?

Kavita K. Trivedi, MD
Valerie Deloney, MBA

Line up for the vaccine but wear a face covering

News of the successful COVID-19 vaccines’ Phase 3 trials has us seeing a light at the end of the tunnel. We’ll need to handle this last leg better if we are to reach the brighter future of herd immunity, though. Packing ourselves some Swiss cheese will help us get there.

Swiss cheese as a metaphor for layered defenses against a threat is popular in many fields, including infection prevention. Each slice of cheese has holes — vulnerabilities and imperfections — but when stacked together, the holes don’t line up and the slices become a solid barrier.

We have a ways to go. Experts estimate 50–75% of the population needs to be immune to SARS-CoV-2 to achieve herd immunity, and we’re at least a year away from that. Why? These vaccines have only been tested on adults; additional trials will need to occur before children get vaccinated. Some people with early access to a vaccine will decline it (as a point of reference, fewer than 50% of people in the US get the annual flu shot). The leading COVID-19 vaccines require two doses, four weeks apart. A percentage of people inevitably won’t show up for the second dose. The logistics for these vaccines are their own complicated puzzle. Last but not least, we’re still learning how long immunity lasts. Fatigued as we are, there’s a journey ahead of us.

There are four evidence-based practices — slices of Swiss cheese — that we individually have the power to implement now, without waiting on new developments or counting on as-yet unavailable supplies. We can implement them today and every day until we emerge on the other side of the pandemic:

a. Face coverings: they protect others by trapping our own germs — and they reduce the amount of virus we inhale if someone else exposes us;

b. Physical distancing while avoiding enclosed spaces (think of spaces where, if a person in it is smoking, the smoke lingers): with 6 feet of distancing and fresh air, if the virus gets around a face covering, it has a hard time reaching a potential host;

c. Staying home when sick or exposed: basic to infection prevention, as well as;

d. Keeping hands clean with soap and water or sanitizer: we touch our faces when we don’t realize it. If our hands are clean, we don’t accidentally deposit the virus there and make ourselves sick.

Together these four simple practices form a nearly solid barrier between us and SARS-CoV-2. Conversely, when we remove slices — for example, when we forgo wearing face coverings — we open up pathways for the virus to spread.

Think of a vaccine as a fifth slice of Swiss cheese. It will fortify our defenses, but collectively we need the other slices to finish the journey.

We’re pretty good at three-quarters of these slices. Most of us have become more diligent about washing our hands. Showing up somewhere sick was iffy pre-pandemic, and now is unthinkable (few will accept exposure to cold-like symptoms because it’s “just allergies”). We used to interact a few feet apart and have become accustomed to judging 6 feet of distance. But when it comes to face coverings, we’ve stumbled.

Every day we’re greeted with an avalanche of information on COVID-19 from experts and non-experts alike. We get it — it’s too much. But turn down the noise, and focus on these four simple practices until we reach the end: using face coverings, physically distancing, staying home when sick or exposed, and cleaning your hands.

We’ll be in line for the first of likely two vaccine injections — standing 6 feet apart with a face covering — but until then, we all need more than hopes, prayers, or excuses. We need actions from many more Americans to stop COVID-19 and get our lives and our economy thriving again.