March 25, 2021
We all need a vacation after a horrendous year of the COVID-19 pandemic, but as we enter the classic period for spring break 2021, public health experts fear yet another surge of COVID-19 will likely emerge across the country.1 What is particularly concerning is the presence of multiple variants of the original SARS-CoV-2, the virus that causes the COVID-19 illness.
Variants of Concern
The new entrants to the COVID-19 pandemic demonstrate minor variations in the genome that determines the composition and shape of the surface proteins surrounding the viral core.2 This in turn causes a change in the infective character of the virus, as well as the way neutralizing antibodies interact with these viral coat proteins.
Figure 1: CDC illustration showing the different SARS-CoV-2 viral coat proteins.
These “Variants of Concern (VOC)” have scientific names, such as B.1.1.7, B.1.351, P.1., B.1.427 and B.1.429. However, they are generally referred to in the press based on their country of origin and/or high prevalence such as Brazil, Great Britain, and South Africa. As of mid-March, a number of these variants have emerged in multiple states3, including places where spring breakers like to party in the sun, such as South Florida, Las Vegas, and South Texas.
All of these variants are reported to be moderately more infectious than the original SARS-CoV-2 genotype and therefore pose a major risk during this spring break. Crowds of young people who have not yet qualified to be vaccinated congregating without exercising mitigation techniques such as wearing masks and staying 6 feet apart to reduce viral spread is the perfect scenario for a massive super-spreader event of these more infective variants.
TSA4 reports that since March 15 an average of 1.3 million travelers has been passing through U.S. Airport security checkpoints every day. In January, the daily average was 761,000. The tide is expected to rise even higher in the weeks to come. Add to this number the thousands of young adults taking the traditional “go cheap” route of packing 4 people into a car for an overnight highway drive both going south to the beach and returning north to get back to classes a week later.
What we all need to be worried about is not just an outbreak in the local population of the southern states after the tide of spring breakers leaves. Also imagine the result of all of these spring breakers returning to their home communities. For example, 4 college friends all share a rental car to drive from a midwest university to Florida for the infamous “senior year break.” During the confined 22 hours in the car driving back, it only takes 1 of the 4 to be recently infected to have all 4 now arrive home to campus ready to spread a new variant of SARS-CoV-2. After 5 days to a week partying unprotected on the beach and (worse) in the clubs, the newly exposed individual is in the peak period of infectivity to others.5 Multiply this risk by the rapidly rising presence of the more highly infectious variants, and you have the making of a COVID-19 firestorm.
Bad Timing: Only Halfway to Herd Immunity
Unfortunately, spring break is occurring right when the light at the end of the tunnel is emerging with multiple vaccines being widely manufactured and now rapidly being administered across the United States. As of March 22, 81 million Americans have had at least one vaccine dose.6
Thus far, just short of 30 million Americans, or 9% of the U.S. population, have been documented as having had COVID-19, according to the World Health Organization.7 The CDC estimates8 the actual number of COVID-19 infections is closer to 83.1 million, as of January 2021. The difference is due to under-reporting, asymptomatic cases, and inefficiencies in the U.S. method of gathering and reporting data. Estimating that the total number of reported and unreported cases has increased to at least 105 million by March 15, 2021, 32% of the U.S population is likely to have had COVID-19.
The percent fully or partially vaccinated (24%) and the number estimated by the CDC as having had some natural immunity to COVID-19 due to past infection (32%) are not independent variables given that perhaps half those getting the vaccine are likely to have had reported or unreported COVID-19. If we add those vaccinated for COVID-19 (24%), and only half of the CDC estimated percent of the U.S. population having had COVID-19 (about 16%), we are approaching 40% of the population unlikely to be at risk of getting a new COVID-19 illness. Public health experts estimate herd immunity to occur when 70 to 90% of the community9 has been vaccinated or made immune by past infection, so we are only halfway to that point.
Unfortunately, the greatest portion of the population who is still at risk, with no history of infection and no vaccination, is the young adult population from 18 to 23 years old, many of whom are likely to be spring breakers. We are so close to the end of this treacherous pandemic, yet we are adding this huge risk factor of mass travel and unprotected social mixing across tens of thousands of people in the susceptible population.
All of us must do what we can to minimize our risks of spreading COVID-19 in the weeks and months to come. No matter what age (if >18 years old), do everything you can to sign up and find access to the COVID-19 vaccine series when it is your turn.
Tips for Travel Safety
To avoid the risks of carrying home the virus and new variants and producing a surge in communities, college dormitories, or classrooms, follow these tips:
For everyone back home, even if you do not travel, monitor your local COVID-19 prevalence rates in your local community and in your county in the 2 to 4 weeks after local schools and universities reopen post-break. The hc1 CV19 Lab Testing Dashboard will reflect your Local Risk Index (LRI), the daily trend line, and the rate of acceleration of an upward trend. An outbreak of a COVID Variant of Concern (VOC) will be reflected as a sharp upward slope of the day-to-day trendline and a high ratio of Current week vs. Previous week ( 7vs.7). This rapid acceleration is caused by the higher infectivity of the VOCs and the large number of individuals who will become infected. All of this local data is available for your hyperlocal community and county by searching your location on the website.
Don’t be the “bad actor” in this COVID-19 drama by bringing back the pandemic to your local community, university, or family. Stay safe, stay healthy, and don’t forget to wear sunblock!