Originally published on April 19, 2021 on Medium
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Expectations are high that we will be able to return to normal in a few months now that, soon, all adults will be eligible for the vaccine, and the vaccination rate is exceeding expectations. A recent article by McKinsey & Company even predicts that we will reach herd immunity by the third quarter of 2021. This comes as a huge relief to everyone, including college and university presidents who are more than eager to see their campuses teaming with students again.
A year ago, colleges and universities turned into virtual institutions overnight as COVID-19 forced everyone into an almost complete lockdown. There was still hope that the pandemic would be seasonal and hence short-lived with warmer temperatures on the horizon. And so, about two-thirds of colleges and universities expected that they could reopen in the fall of 2020. We were not as optimistic and argued in June of last year for online instruction for the fall semester. A couple of months later, in August, we predicted that colleges would be online for the entire academic year. In fact, that is what happened. Almost all colleges and universities opted for online for the entire academic year.
As we look forward to the fall 2021 semester, we see that colleges and universities are preparing again for a return to face-to-face instruction in the upcoming fall semester. With the prospect that a high percentage of people in the U.S. will be vaccinated soon, the expectation is that a few months from now, thousands of students will be able to come back on campus. While we are optimistic that colleges and universities will return to face-to-face instruction in the fall, we are starting to wonder whether evolving realities will allow them to stay open.
EXPECTED VACCINATION RATES AND NEW VARIANTS MIGHT THWART OUR EFFORTS
It is likely that everyone in the U.S. will have had the opportunity to be fully vaccinated by July 4. However, having the opportunity to get vaccinated and getting vaccinated are not the same. Vaccine hesitancy continues to be a problem. The weekly Household Pulse Survey for March 3 to March 15, conducted by the U.S. Census Bureau, shows that 17.6% of adults will probably or definitely not get the COVID-19 vaccine. Among those under age 40, the percentages are even higher (Figure 1).
Figure 1: Percentage of adults by age who will probably/definitely not get vaccinated (Source: Week 26 Household Pulse Survey: March 3 – March 15)
The percentage of unprotected adults will even be higher since not everyone who is vaccinated will be protected: Under real-world conditions, the effectiveness of the Pfizer-BioNTech or Moderna vaccines was reported to be 90% in a recent CDC report. Adding together the number of adults who will probably or definitely not get the COVID-19 vaccine and those for whom the vaccine will fail, we find that about 26% of adults who are exposed would not be protected. In the age group of 18-24 year-old adults, which includes most college students, almost 30% would not be protected.
Complicating the situation is the steady rise of new variants that may compromise the effectiveness of the vaccines that were developed to protect against the original strain. The vaccines appear to remain effective against B.1.1.7, the variant that was first detected in the U.K. and is now the most prevalent variant in the U.S. There is evidence emerging that the vaccines have reduced effectiveness against B.1.351, the variant that was first detected in South Africa. The Brazil variant P.1 is even more challenging as there is increasing evidence that it is not only highly transmissible but also able to re-infect individuals who have already had COVID-19. As more and more people are vaccinated, the selection pressure on the virus to escape immunity will increase, and if the number of daily new infections stays high, the virus will have plenty of opportunities to explore pathways to escape immunity.
WE MIGHT CONTINUE TO SEE TENS OF THOUSANDS OF DAILY NEW CASES
We have seen three pandemic waves so far in the U.S. (Figure 2). The third wave lasted from October to February, fueled by Thanksgiving and Christmas get-togethers. During this period, the U.S. had 21.4 million diagnosed cases of COVID-19. After the holidays, many people reduced face-to-face interactions with others again. The number of daily new cases plummeted. But we still see well above 50,000 daily new cases of COVID-19.
Figure 2: Daily new COVID-19 cases (source: Johns Hopkins University)
CAN WE REACH HERD IMMUNITY?
For the past 6 months, many have hoped that our ability to reach herd immunity, believed to be around 80%, will allow us to go back to life as it was before COVID. Hopes are particularly high in states where the number of daily new cases is low. For instance, the Texas’ governor suggested that the combination of those vaccinated in Texas and those who have been infected with COVID-19 could mean that Texas “could be very close to herd immunity.” With only 33% of the total population having received at least one dose of the vaccine in Texas, Michael Osterholm, an epidemiologist and director of the University of Minnesota’s Center for Infectious Disease Research and Policy, replied that “[t]here is no way on God’s green earth that Texas is anywhere even close to herd immunity.”
We may not reach herd immunity anytime soon in the U.S. The gains we make by reducing infections because of vaccination may be offset not only by the appearance of new variants but also by the increased number of interactions among people. As more and more people are getting vaccinated, it will be increasingly difficult to get people in the U.S. to continue the restrictions. Many states such as Florida and Texas have rescinded any coronavirus restrictions and even in states where COVID cases are escalating rapidly, like in Michigan, the will to restrict individual behavior is low. People are starting to travel, visit family and friends, eat indoors in restaurants, and attend baseball games and movie theaters without wearing masks and physical distancing.
The question then becomes how many daily new infections we should expect. We believe that the level of infection will be controlled largely by what level we are willing to tolerate. Over the past twelve months, we have developed a high level of tolerance for large numbers of infections. In the early months of the pandemic, 30,000 daily new cases felt a lot. Now, we barely blink an eye if the numbers exceed 60,000. With the vaccination greatly reducing the risk of death or severe disease, we will likely be willing to tolerate even larger numbers of daily new cases unless we observe a significant increase in hospitalizations again, increased rates of death (again) or conclude that the risk of long COVID is unacceptably high. We know this since we readily accept an average of about 150,000 flu cases per day during the 6-month flu season.
MANDATORY VACCINATION IS THE SOLUTION
To control outbreaks, we need to gain a better understanding of what activities are particularly risky to become super spreader events. We already know that becoming infected requires relatively close contact with an infected person over a sustained period of time. Large crowds are favorable places for that. But a large crowd by itself is not enough to turn an event into a super spreader event. The people who are contagious must also move around among susceptible people.
If a contagious person visits a full movie theater and about 30% of the audience are susceptible, chances are that the person will infect someone else. The number of new infections, however, will be comparatively small since people don’t move around much when watching a movie. If the same number of people are in a bar where they constantly move around and talk at close distance and high volume with different people, the number of infections will likely be much higher.
Colleges are more like bars than movie theaters. While the risk of infection in a classroom may be small, students move around and constantly change to whom they are close. They attend multiple classes per day, sitting next to different students, go to lunch or study with a different set of students, and socialize in the evening with yet a different set of students. A student can easily interact with tens of students each day for prolonged periods of time.
The constant mixing of students puts colleges and universities at high risk for outbreaks. An outbreak can quickly force a university to isolate a potentially large number of students or, worse, shut down again. The likelihood that infected people are on campus on any given day is not small if we end up tolerating tens of thousands of daily new infections: Even if we have on average only about 20,000 daily new infections nationwide, a university campus with 50,000 students could see several hundred contagious students showing up each semester. With about 30% of students in the typical college-age group likely not being protected, the likelihood of a local outbreak during a semester becomes high.
One way out of regular outbreaks is to require vaccination of college students (with the standard exceptions that are common for other mandatory vaccinations). A number of colleges have already announced that they will require proof of vaccination by the first day of fall classes. Mandatory vaccination is not popular in some places and is quickly becoming a political battle ground. But it should be noted that mandatory vaccination for colleges and universities would not be a new idea. For years, many states have legally required college students to be vaccinated against Hepatitis B, measles, mumps and rubella and meningococcal disease, even in states, like Texas, where colleges and universities are not allowed to require proof of vaccination against COVID-19. The Emergency Use Authorization (EUA) status of coronavirus vaccines and the fact that the vaccines are still relatively new may complicate that ability of universities to require vaccination.
Mandatory vaccination against COVID-19 will be more burdensome if annual booster shots will become the norm to protect against new variants and potentially waning immunity. But the alternative would be to continue the test and isolate regime on campuses to avoid or at least control recurrent outbreaks that would be quite disruptive for college life. Even with successful vaccination efforts, it is likely that some of the current protective measures that universities employ to prevent the spread of COVID will have to remain (masking, social distancing and some sort of regular testing regime). Recurrent outbreaks would take a toll on instruction as every class would need an online option if we want to make sure that quarantined or isolated students can continue to make progress. It would also take a toll on residential life and co-curricular activities. Students who suffer from medical conditions that either make the vaccine less effective or cannot be vaccinated would live in constant fear of getting infected.
New variants, waning immunity, and lack of vaccination in too many people will work against us returning to a normal life. States have the option to make vaccination against COVID-19 mandatory for all students enrolled in colleges and universities that offer face-to-face instruction. If they don’t, we may see Spring 2022 going online again.