The United States is once again seeing a rise in Covid-19 cases. The vaccination campaign under the Biden administration has picked up significant speed, but so has circulation of variants of concern.
A variant detected in South Africa, B1351, blunted the efficacy of Johnson & Johnson’s vaccine there. And a third variant, identified in Brazil and known as P1, could reinfect people who previously were immune to the coronavirus.
All this comes at a time when many Americans assumed the nation would move in the direction of a new “normal”, thanks to incredible achievements in vaccine technology.
So what do these competing ideas mean as the vaccine rollout battles the spread of the variants?
Dueling trends are causing uncertainty.
Cases and hospitalizations have increased in the last week, with especially pronounced rises in Florida, Michigan, New Jersey, New York and Pennsylvania that experts attribute to the B117 variant. Nationally, cases have increased 10% from the previous seven days.
“We have so much to look forward to,” said the US Centers for Disease Control and Prevention (CDC) director, Dr Rochelle Walensky, in a Covid taskforce briefing this week. “But right now I’m scared.” In an off-script moment, Walensky said infections, hospitalizations and deaths, which are a lagging indicator, gave her a sense of “impending doom”.
But the uptick in variants of concern are only part of the picture. People are also showing an increased willingness to abandon masks, stop social distancing and begin to travel.
“I don’t think the sky is falling, but what I am concerned about is the rise in mobility and decline in mask-wearing,” said Professor Ali Mokdad, chief strategy officer for population health and a Covid-19 forecaster at the Institute for Health Metrics and Evaluation at the University of Washington. “These are the two indicators we need to keep an eye on”.
Models from Mokdad’s university predict a slight bump in cases, followed by an ongoing decline. That decline will be aided by mild weather, the vaccination campaign and outdoor activities.
Why are forecasters disagreeing now?
One-sixth of the US population is now fully vaccinated and 28.9% have had at least one dose. This week, new studies showed vaccines remained 90% effective in real life, and held out the promise of very effective vaccines for older children.
But this is still too low a rate to put the brakes on viral spread, and human behavior remains a wild card.
Unlike other moments in the pandemic, there are signs people have faith the pandemic is improving, even though cases remain very high. Democratic and Republican governors are lifting mask mandates, allowing more indoor dining and lifting restrictions on sports stadiums and entertainment venues. People also appear more willing to travel and are booking plane and cruise tickets for the near future.
That has resulted in dramatic variation in viral spread forecasts in coming weeks. Some predict a decrease and others an increase. The uncertainty of the moment is visible in an ensemble forecast of cases collected by the US Centers for Disease Control and Prevention (CDC).
The Biden administration has asked people to continue social distancing and mask-wearing, and encouraged health leaders to widen vaccine eligibility criteria. But ultimately, with a federalized public health system, states are in charge of their response.
“I don’t see us, quite honestly, in the summer [having] a wave as big as we had before, or as big as the last summer, simply because vaccines are being rolled out as fast as we can,” said Mokdad. However, that is “conditional” on no new variants “showing up and making the vaccine less effective”.
Could more variants of concern emerge?
In short: yes. Vaccines are a static solution to a moving target – an evolving virus. Existing and future virus mutations hold the potential to blunt vaccine efficacy. They are one reason many experts believe booster shots for Covid-19 may be necessary in the future.
Further, Mokdad believes the US will need to be more vigilant about Covid-19 outbreaks next winter, when fewer people will be able to pursue activities outdoors, and some people continue to hesitate about taking a vaccine.
And a partially vaccinated population puts pressure on the virus to evolve to find more hosts. Already, the National Institute of Allergy and Infectious Diseases (Niaid) is studying a B1351 variant vaccine with Moderna.
This sounds very scary.
There are also hopeful signs. The pace of vaccination is rapid. More and more US adults are getting vaccinated. But challenges will emerge as the US vaccine shortage becomes a glut.
Millions of Americans still lack the computer access or transportation necessary to obtain a vaccine. Children younger than 16 represent roughly one quarter of the population, but are not yet eligible for vaccines. And certain populations are especially hesitant to be vaccinated, such as white Republican men.
Will the public continue to get vaccinated? Will people abandon social distancing? Will travel increase? All these unknown elements of how people will act make it incredibly difficult to predict where the pandemic is headed right now.
What is certain is it is too early for the Americans to let their guard down.