Looking back, and forward
What’s happening in Europe today mirrors past COVID-19 spikes that presaged big upticks in cases, hospitalizations, and deaths in the United States.
When the pandemic first hit Europe in March 2020, then-President Donald Trump downplayed the threat of the virus despite the warnings of his own advisors and independent public health experts who said COVID-19 could have dire impacts without an aggressive federal action plan.
By late spring the United States had become the epicenter of the pandemic, when case totals eclipsed those of other countries and New York City became a hot zone, according to data compiled by the Johns Hopkins Coronavirus Resource Center. Over the summer, spread of the disease slowed in New York, after tough control measures were instituted, but steadily increased in other states.
Then, later in the year, the Alpha variant of the virus took hold in the United Kingdom and the United States was again unprepared. By winter, the number of cases accelerated in every state in a major second surge that kept millions of Americans from traveling and gathering for the winter holidays.
With the rollout of COVID vaccines last December, cases in the United States – and in many parts of the world – began to fall. Some experts even suggested we’d turned a corner on the pandemic.
But then, last spring and summer, the Delta variant popped up in India and spread to the United Kingdom in a third major wave of COVID. Once again, the United States was unprepared, with 4 in 10 Americans refusing the vaccine and even some vaccinated individuals succumbing to breakthrough Delta infections.
The resulting Delta surge swept the country, preventing many businesses and schools from fully reopening and stressing hospitals in some areas of the country – particularly southern states – with new influxes of COVID-19 patients.
Now, Europe is facing another rise in COVID, with about 350 cases per 100,000 people and many countries hitting new record highs.
What’s driving the European resurgence?
So, what’s behind the new COVID-19 wave in Europe and what might it mean for the United States?
Shaun Truelove, PhD, an infectious disease epidemiologist and faculty member of the Johns Hopkins School of Public Health, says experts are examining several likely factors:
Waning immunity from the vaccines. Data from Johns Hopkins shows infections rising in nations with lower vaccination rates.
The impact of the Delta variant, which is three times more transmissible than the original virus and can even sicken some vaccinated individuals.
The spread of COVID-19 among teens and children; the easing of precautions (such as masking and social distancing); differences in the types of vaccines used in European nations and the United States.
“These are all possibilities,” says Dr. Truelove. “There are so many factors and so it’s difficult to pinpoint exactly what’s driving it and what effect each of those things might be having.”
As a result, it’s difficult to predict and prepare for what might lie ahead for the United States, he says.
“There’s a ton of uncertainty and we’re trying to understand what’s going to happen here over the next 6 months,” he says.
Even so, Dr. Truelove adds that what’s happening overseas might not be “super predictive” of a new wave of COVID in the United States.
For one thing, he says, the Pfizer and Moderna vaccines, the two mRNA vaccines used predominantly in the United States, are far more effective – 94-95% – than the Oxford/AstraZeneca COVID shot (63%) widely administered across Europe.
Secondly, European countries have imposed much stronger and stricter control measures throughout the pandemic than the United States. That might actually be driving the new surges because fewer unvaccinated people have been exposed to the virus, which means they have lower “natural immunity” from prior COVID infection.
Dr. Truelove explains: “Stronger and stricter control measures … have the consequence of leaving a lot more susceptible individuals in the population, [because] the stronger the controls, the fewer people get infected. And so, you have more individuals remaining in the population who are more susceptible and at risk of getting infected in the future.”
By contrast, he notes, a “large chunk” of the United States has not put strict lockdowns in place.
“So, what we’ve seen over the past couple months with the Delta wave is that in a lot of those states with lower vaccination coverage and lower controls this virus has really burned through a lot of the susceptible population. As a result, we’re seeing the curves coming down and what really looks like a lot of the built-up immunity in these states, especially southern states.”
But whether these differences will be enough for the United States to dodge another COVID-19 bullet this winter is uncertain.
“I don’t want to say that the [Europe] surge is NOT a predictor of what might come in the U.S., because I think that it very well could be,” Dr. Truelove says. “And so, people need to be aware of that, and be cautious and be sure get their vaccines and everything else.
“But I’m hopeful that because of some of the differences that maybe we’ll have a little bit of a different situation.”