The United States is in the midst of what may be its biggest summer wave of Covid, with no end in sight.
“If we’re just talking about infections, this is likely to be the largest summer surge we’ve seen,” said Dr. Ashish Jha, dean of the Brown University School of Public Health and a former White House COVID-19 response coordinator. “It’s not as large as the winter surges yet, but it’s starting to get close.”
It’s not just the United States. There has been a global surge in infections in recent weeks, Dr. Maria Van Kerkhove, the World Health Organization’s technical lead on Covid, said at a briefing this week. The proportion of positive Covid tests in Europe is over 20%, with wastewater data suggesting the number of cases could be two to 20 times higher than reported, Van Kerkhove said.
The best way to estimate how much virus the United States is dealing with is to look at wastewater data from the Centers for Disease Control and Prevention, since many people are simply doing home tests when they get sick, if they do at all.
Nationally, the CDC says COVID levels are “high,” with the western United States, including Texas and California, seeing some of the highest levels of the virus. Eastern states, such as Florida and North Carolina, are also reporting very high levels of the virus in the community.
Wastewater does not identify the number of cases per day; coronavirus levels are much higher nationally than they were at the same time last year.
This year’s summer surge also started earlier than last year’s, Jha said. The number of cases started rising in early June, compared to July and August 2023.
Jha expects this wave to peak in the coming weeks, with case numbers becoming much lower around September — around the time updated Covid vaccines targeting the KP.2 strain, a descendant of the JN.1 variant, are expected to become available.
The new vaccines are expected to receive final approval from the Food and Drug Administration in the coming weeks. At that time, the CDC will recommend who should be first in line to receive the shots.
Jha said that to protect against a winter wave, You should consider getting vaccinated no earlier than October, although any time before Thanksgiving should be fine.
Andrew Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, didn’t expect the summer waves to be so pronounced four years after Covid began.
“I and many other virologists thought we would probably see summer waves for another year or two, but we didn’t expect them to increase significantly,” he said. “We thought they would continue to get smaller and smaller over time, whereas we were hoping it would be just one winter wave of Covid cases per year.”
The CDC’s latest forecast suggests a mix of variants currently circulating, including KP.3, KP.3.1.1, and KP.2.3, descendants of JN.1. version of the virus that was circulating earlier this year. Some scientists call these variants “FLiRT” — a reference to their genetic modifications — and they are considered among the most contagious yet.
The factors driving the current spread are most likely the more transmissible variants, combined with people spending more time indoors due to warm weather, he said.
“Other than that, there’s not much we can put our finger on to say that this is what’s driving this summer surge,” Pekosz said.
Overall, Covid-19 hospitalizations have remained lower than last year. In the last summer months, there has been a slight increase, with levels higher than at the same time last year. Fortunately, deaths from Covid-19 remain the lowest on record.
“We’re seeing people who are hospitalized and testing positive for COVID, but serious pulmonary complications from COVID-19 are extremely rare,” said Dr. Michael Phillips, chief epidemiologist at NYU Langone Health in New York City. “We’re seeing a dramatic increase in the number of people who are coming to our emergency departments or going to our outpatient sites and testing positive and going home.”
The test positivity rate at NYU Langone Health, or the proportion of patients with symptoms who test positive for COVID, is 12%, a six-fold increase in just the past two months.
Last month, the hospital recorded 1,357 positive tests, more than double the number recorded in July 2023, when it recorded 562. Only 12 of the Covid-19 patients were admitted to hospital last month for Covid-19-related illnesses.
“Our hospitalization rates are down, so even though we are testing and seeing more (Covid) cases, it seems to be having less of an impact on our susceptible populations,” Phillips said.
Jha said it was impossible to predict what would happen this winter, but a big summer surge could have a silver lining.
“A big summer wave tends to lead to a slightly smaller winter wave and vice versa, simply because there is a little bit more immunity in the population,” he said.
