Old U.S. Covid-19 Hot Spots Are the New Hot Spots

The recent rise in Covid-19 cases in the U.S. has largely been driven by a handful of states, many of them the same places that first emerged as hot spots a year ago. Through Monday, about 75% of the previous week’s new cases in the U.S. came from Michigan, Florida, New York, Pennsylvania and New Jersey.

Covid-19 cases and the rate of new cases per 100,000 people are resurging in several states that, for long stretches, had kept the pathogen relatively at bay. Outside of the period from Thanksgiving to New Year’s, Michigan, Pennsylvania and New Jersey haven’t seen levels this high during the pandemic. And outside of that same holiday period, New York hasn’t had this many new cases since spring, and Florida not since the summer.

Public-health officials and epidemiologists say the increasing caseloads in many parts of the country can be attributed to a constellation of factors, including the spread of more transmissible variants; a rise in infections among younger, often unvaccinated, people; relaxed prevention efforts and loosened restrictions on indoor dining and masking; as well as pandemic fatigue.

A Familiar Pattern

Following a sharp drop from the deadly fall surge, newly reported Covid-19 cases have remained elevated across the U.S. But some states have seen cases jump back higher again. They seem to follow a familiar pattern. When cases reached their first peak in mid-April 2020, New Jersey, Michigan, Pennsylvania and New York were leading that surge.

However, when the nation reached a new peak in late July, those four states were at low points as the pandemic center moved South and West. They rose again in winter, along with the rest of the U.S., and now are the driving force behind this year’s latest rise.

Covid-19 cases per 100,000

Epidemiologists and public-health authorities in Michigan have pointed to school sports as a major source of Covid-19 transmission. In addition, nationwide, large outbreaks have been tied to the recent Easter holiday and spring breaks.

Rise in Variants

The U.K. variant is now the dominant variant in the U.S. The upper Midwest, including Michigan and Minnesota where cases have been elevated, has some of the largest known case counts of the U.K. variant. Instances of the strain are also high in Tennessee and Florida. The variant has been reported in every state.

Regional versions of the virus, first detected in New York and California, are also gaining ground. Like the U.K. variant, these may be more transmissible than the earlier versions of the virus, researchers suspect.

Prevalence of more infectious variants initially detected in South Africa and Brazil remains low in the U.S., but given the lack of widespread genetic sequencing, the Centers for Disease Control and Prevention can’t provide accurate incidence rates for all of them.

The Biden administration announced Friday a $1 billion investment to expand genomic sequencing across the CDC, states and jurisdictions, as part of the $1.9 trillion Covid-19 relief package signed into law last month. The money will support the collection of Covid-19 specimens, sequencing and data-sharing to help identify mutations of the virus.

Younger People Infected

Older patients have traditionally experienced more severe cases of Covid-19, with higher rates of deaths and hospitalizations. Higher vaccination rates among older people, who were given priority for immunizations, have started to reshape that trend—which may be contributing to the increased proportion of severe cases among younger patients.

Recently, infections and hospitalizations among people under age 55 have been increasing.

“Hospitals are seeing more and more younger adults—those in their 30s and 40s—admitted with severe disease,”

Dr. Rochelle Walensky,

director of the CDC, said at a news briefing recently. “And so what we really want to do is just scale up that vaccination more and more and more so that we can be in a place where we have…more vaccinations out there, and really less disease circulating.”

Some 25.4% of people in the U.S. have been fully vaccinated, according to data from the Centers for Disease Control and Prevention. Around 50.4% of Americans aged 18 and older, and 39.5% of the total population, have received at least one vaccine dose, the CDC data show.

Newly reported cases declined from a day earlier, with 42,018 reported for Sunday after 52,373 were reported for Saturday, according to the latest data compiled by Johns Hopkins University. The number of new cases recorded each day tends to be lower at the beginning of the week, as fewer people are tested and many states don’t report data on weekends.