Biden’s first 100 days require 200 million vaccinations
In its first year, the novel coronavirus-19 (SARS-CoV-2) has caused over 20 million infections in the U.S., leading to nearly 350,000 deaths. Currently there are over 120,000 patients hospitalized with the virus, stressing the health care system to its breaking point. The number of new cases per day has climbed above 200,000, absolutely precluding contact tracing as a useful control measure. The pandemic is out of control in our country, and January and February will record its darkest impact. An added threat is the emergence and increasing prevalence of the U.K. variant with its increased transmissibility.
Despite the emergency use approval of two very effective vaccines from Pfizer and Moderna, the cash-strapped states are struggling to deliver enough doses to reach the 60 percent vaccinated population targeted for herd immunity. Although many have offered reassuring statements that the U.K. variant does not increase mortality or reduce the vaccine efficacy, a look at the numbers shows a grim possibility if we fail to stop transmission now.
The case reproduction number (Ro) is the estimate of the average number of secondary cases for each primary infection. For SARS-CoV-2, it has been estimated to be from 1.5 to 2.5. If Ro is greater than 1, the pandemic persists; if it falls below 1, the pandemic recedes. With an Ro of 2, for each 10 primary cases, there will be 20 secondary infections. On a national level, the 200,000 new cases daily translates to 400,000 secondary cases.
A complicating factor is that transmission is not similar for everyone: 10 percent of infected people account for 80 percent of transmissions. These are the superspreaders found at indoor venues who deserve our immediate focus. Recall that the crude rates of infection are 20 times greater indoors than outdoors. In the example above, the 400,000 secondary cases are influenced primarily by the 320,000 cases (80 percent) accounted for by the superspreaders.
The new variant is thought to have 70 percent greater transmission than the standard strain with its Ro of 2. If the new variant replaces all current strains, the virus will have an Ro of 3.4. That translates not to 400,000 secondary cases but to 680,000, of which 544,000, or 80 percent, are from superspreaders. Furthermore, the incremental 280,000 secondary cases will lead to an excess 2800 deaths per day if mortality is 1 percent.
Now imagine if we’re effective at closing down all indoor superspreading events— bars, restaurants, gyms, weddings, religious services, private parties, etc.—while maintaining an invigorated focus on nursing homes, where 40 percent of all COVID-19 related deaths have occurred. We might reduce the Ro by 80 percent, taking it from 3.4 down to 0.68. By definition the pandemic would slow down.
For this to occur, there needs to be a strict policy instituted immediately until we have herd immunity. We need to continue with strict social distancing, mandates for use of masks, and a social contract to contribute to the health of our society. Of interest, a recent report showed that Japan achieved great success in minimizing the impact of COVID-19 without major shutdowns or widespread testing. With the lowest rate of deaths in the G-7, 18 per million, the Japanese attribute their success to a focus on superspreading events coupled with a national emphasis on avoiding closed spaces, crowds and close contact.
The COVID-19 variant is now in at least 33 countries and so far it has been identified in a few states in the U.S. Though it does not increase rates of death, the large increase of secondary cases as it replaces the current strain will cause incrementally more cases, hospitalizations, deaths, and stress on the health care system. We need a major goal to eliminate the superspreading events completely. To minimize the trajectory of this unforgiving virus, the current threats also suggest an urgent need for the incoming Biden administration to greatly accelerate the production and delivery of effective vaccines, from 100 million doses in the first 100 days to 200 million doses.
Richard P. Wenzel, MD,MSc, is an infectious disease epidemiologist at Virginia Commonwealth University in Richmond. He is editor-at-large of The New England Journal of Medicine. Wenzel also serves as emeritus professor and former chair of the Department of Internal Medicine at VCU and has been president of both the Society for Healthcare Epidemiologists of America and The International Society for Infectious Diseases.
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