By early next week, the share of the U.S. population that has received at least one dose of the coronavirus vaccine should reach 10%.
With the winter surge of COVID-19 receding, the next few weeks of the vaccination campaign will determine whether the country will be on the path toward normalcy as early as the spring, epidemiologists say.
Roughly a quarter or more of the population has been infected with the virus and recovered, according to estimates from the Centers for Disease Control and Prevention. The vaccination program has targeted many of the groups most vulnerable to severe cases of COVID-19. Altogether, it appears the country is headed toward a substantial level of protection from COVID-19.
Yet the threat of the rise of new, faster-spreading variants of the virus threaten to make the situation worse before it gets better.
Accordingly, whether the United States can quickly and permanently lower COVID-19 deaths and hospitalizations “depends on rollout speed and how many people are in the older demographic” for vaccinations, said Daniel Larremore, a computer science professor at the University of Colorado, Boulder and the BioFrontiers Institute.
Larremore is the co-author of an article published in Science finding that if those ages 60 and up were prioritized, then the U.S. should see a 30% reduction in COVID-19 deaths once 10% of the population receives both doses of either the Pfizer or Moderna vaccine. However, if the infection rate rises from 1.15 to 1.5, then the death rate drops by only about 25%.
Another recent paper, which has not yet been peer-reviewed, examined what would happen if 20% of the population were vaccinated versus 40%. Under the first scenario, hospitalizations in intensive care units fell 62%, while under the second scenario, they fell 85%.
Seyed Moghadas, the lead author on the paper and a professor of applied mathematics and computational epidemiology at York University in Toronto, agreed that how quickly the U.S. vaccinates is crucial.
“A key parameter is the speed of vaccination,” Moghadas said. “The faster we vaccinate … the larger the impact of vaccination.”
Moghadas’s paper assumes that 1 million people would be vaccinated daily, while the paper in Science assumes about 0.2% of the population is vaccinated daily. The U.S. appears to be ahead of those rates. In the last week, almost 1.3 million people, about 0.4% of the population, were vaccinated daily, based on data from the CDC. However, only 6.4 million people in the U.S. have received a second dose. That is a daily rate of about 380,000 or just over 0.1% of the population. Both papers assume that people have received both doses of the vaccine.
Both Israel’s and the United Kingdom’s experience suggest that the speed of the vaccination effort is vital. Both nations’ emphasis on vaccinating the elderly are showing early promise. Nearly 7 in 10 Israelis ages 60 and up have received a second dose of the vaccine. In the last two weeks, Israel has experienced a nearly 35% drop in cases of COVID-19 and a 30% drop in hospitalizations.
Over the last week, the U.K. has experienced a decline in hospital admissions for those age 65 and older. However, scientists say that it is premature to draw any definitive conclusions from the data. Still, the U.K. has been aggressive in its vaccine campaign, immunizing 15% of the population since December, including 90% of those age 80 and older and half of those age 70 and up.
There are about 54 million people in the U.S. age 65 and older. How many have received at least one dose of the vaccine is not presently known. However, chances are good that it is at least 10% as over 4.2 million vaccines have been administered to those in nursing homes.
Larremore said that the U.S. could see significant improvement within the next few months if more vaccines are approved by the Food and Drug Administration.
“Optimistically, late spring or early summer, we’ll hope to see drops in deaths and infections … in a much more sustained way,” he said. “But that is going to be contingent on whether we get approval and rollout of vaccines from Novavax, Johnson & Johnson, and AstraZeneca.”
The AstraZeneca vaccine has already been given emergency approval in the U.K. and the European Union but probably won’t be approved in the U.S. until April. Johnson & Johnson’s vaccine could be approved for emergency use in the U.S. by March, while the Novavax vaccine could be ready by June.
Moghadas is more pessimistic.
“A lot depends on vaccination rates and the dynamics of new strains of the coronavirus that are more transmissible,” Moghadas said. “What is certain is that until we increase vaccination rates to about 2 to 3 times higher than currently being administered in the U.S. … and communicate with the public to go and get the vaccine for their own benefits while protecting others, controlling the pandemic may stretch to 2022.”
