Children Likely the ‘Leading Edge’ in Spread of COVID-19 Variants

Public health officials in the Midwest and Northeast are sounding the alarm about steep new increases in COVID-19 cases in children.

The increases seem to be driven by greater circulation of more contagious variants, just as children and teens have returned to in-person activities like sports, parties, and classes.

“I can just tell you from my 46 years in the business, I’ve never seen dynamic transmission in kids like we’re seeing right now, younger kids,” said Michael Osterholm, PhD, who directs the Center for Infectious Disease Research and Policy at the University of Minnesota, Minneapolis.

In earlier surges, children — especially younger children — played only minor roles in transmitting the infection. When they were diagnosed with COVID-19, their symptoms tended to be mild or even absent, and for reasons that aren’t well understood, they haven’t usually been the first cases in households or clusters. 

Now, as more SARS-CoV-2 variants have begun to dominate, and seniors gain protection from vaccines, that pattern may be changing. Infectious disease experts are watching to see if COVID-19 will start to spread in a pattern more similar to influenza, with children becoming infected first and bringing the infection home to their parents.

Michigan Sees Jump in Cases

Governors in some hard-hit states are pleading with a pandemic-weary public to keep up mask-wearing and social distancing and avoid unnecessary travel and large gatherings in order to protect in-person classes. 

In Michigan, many schools reopened and youth sports resumed just as the more contagious B.1.1.7 variant spread widely. There, cases are rising among all age groups, but the largest number of new COVID-19 cases is among children ages 10-19, the first time that’s happened since the start of the pandemic.

Over the past month, incidence in this age group has more than doubled in the state. Cases among younger children — infants through 9-year-olds — are also going up, increasing by more than 230% since February 19, according to data from the Michigan Department of Health and Human Services. 

The increases have prompted some schools to pause in-person learning for a time after spring break to slow transmission, according to Natasha Bagdasarian, MD, senior public health physician with the Michigan health department in Ann Arbor.

In Minnesota, on a recent call with reporters, Ruth Lynfield, MD, state epidemiologist, said the B.1.1.7 variant, which has rapidly risen in the state, has a higher attack rate among children than earlier versions of the virus, meaning they’re more likely to be infected when exposed.

“We certainly get the sense that youth are what we might refer to as the leading edge of the spread of variants,” she said.

Lynfield said they were tracking cases spreading through youth sports, classrooms, and daycare centers.

In Massachusetts, the largest number of new COVID-19 infections in the last 2 weeks was among children and teens. Massachusetts has the fifth-highest number of recorded B.1.1.7 cases in the United States, according to CDC data.

Although most COVID-19 cases in children and teens are mild, the disease can be severe for those who have underlying medical conditions. Even in healthy kids, it can trigger a serious postviral syndrome called MIS-C that requires hospitalization. 

Emerging studies also show that children, like adults, can develop the lingering symptoms of long COVID. Recent data from the United Kingdom show 10%-15% of children younger than 16 infected with COVID-19 still had at least one symptom 5 weeks later.

Osterholm said it remains to be seen whether more cases in children will also mean a rise in more serious outcomes for kids, as it has in Europe and Israel.

In Israel, the B.1.1.7 variant arrived at the end of December and became dominant in January. By the end of January, Hadassah Ein Kerem Medical Center in Jerusalem had four patients in its newly opened pediatric COVID ICU unit. They ranged in age from 13 days to 2 years.

By early February, the Ministry of Health warned the country’s doctors to prepare for an “imminent upward trend” in pediatric COVID-19 cases. They notified hospitals to be ready to open more ICU beds for children with COVID-19, according to Cyrille Cohen, PhD, head of the laboratory of immunotherapy at Bar-Ilan University in Ramat Gan, Israel.

On Wednesday, French President Emmanuel Macron ordered France into its third national lockdown and closed schools for 3 weeks to try to hold off a third wave of COVID-19. Macron had been a staunch defender of keeping schools open, but said the closure was necessary.

“It is the best solution to slow down the virus,” he said on Wednesday, according to Reuters.

German Chancellor Angela Merkel also recently announced a new lockdown for Germany as the spread of the variants has led to rising cases there.

“I think what we’re seeing here is this is going to play out over the country,” said Osterholm. “Before this time, we didn’t see major transmission in younger kids particularly K through eighth grade, and now we’re seeing that happening with many school outbreaks, particularly in the Northeast and in the Midwest.” He added that it will spread through southern states as well.

Fall Surge All Over Again

“It’s starting to feel an awful lot like déjà vu, where the hospitalization numbers, the positivity rate, all of the metrics that we track are trending up significantly, and it’s feeling like the fall surge,” said Brian Peters, CEO of the Michigan Hospital Association. “It’s feeling in many ways like the initial surge a year ago.”

Peters says in January and February, COVID-19 hospitalizations in Michigan were less than 1000 a day. One day this week, he said, there were 2558 people hospitalized with COVID-19 in Michigan.

About half of adults ages 65 and older have been fully vaccinated in Michigan. That’s led to a dramatic drop in cases and hospitalizations among seniors, who are at highest risk of death. At the same time, Gov. Gretchen Whitmer and health officials with the Biden administration have encouraged schools to reopen for in-person learning, and extracurricular activities have largely resumed.

The same circumstances — students in classrooms, combined with the arrival of the variants — resulted in COVID-19 cases caused by the B.1.1.7 variant increasing  among younger age groups in the UK. 

When schools were locked down again, however, cases caused by variant and wild type viruses both dropped in kids, suggesting that there wasn’t anything that made B.1.1.7 extra risky for children, but that the strain is more contagious for everyone. Sports, extracurricular activities, and classrooms offered the virus plenty of opportunities to spread.

In Michigan, Bagdasarian said the outbreaks in kids started with winter sports.

“Not necessarily transmission on the field, but we’re really talking about social gatherings that were happening in and around sports,” like the pizza party to celebrate a team win, she said, “and I think those social gatherings were a big driver.”

“Outbreaks are trickling over into teams and trickling over into schools, which is exactly what we want to avoid,” she added.

Thus far, Michigan has been reserving vaccine doses for older adults but will open eligibility to anyone age 16 and older starting on April 6.

Until younger age groups can be vaccinated, Peters said people need to continue to be careful.

“We see people letting their guard down and it’s to be expected,” Peters said. “People have COVID fatigue, and they are eager to get together with their friends. We’re not out of the woods yet.”

Children “Heavily Impacted”

In Nebraska, Alice Sato, MD, PhD, hospital epidemiologist at Children’s Hospital and Medical Center in Omaha, said they saw an increase in MIS-C cases after the winter surges, and she’s watching the data carefully as COVID-19 cases tick up in other midwestern states.

Sato got so tired of hearing people compare COVID-19 to the flu that she pulled some numbers on pediatric deaths.

While COVID-19 fatality rates in children are much lower than they are for adults, at least 279 children have died across the US since the start of the pandemic. The highest number of confirmed pediatric deaths recorded during any of the previous 10 flu seasons was 188, according to the CDC.

“So while children are relatively spared, they’re still heavily impacted,” said Sato.

She was thrilled to hear the recent news that the Pfizer vaccine works well in children ages 12-15, but because Pfizer’s cold-chain requirements make it one the trickiest to store, the FDA hasn’t given the go-ahead yet. She said it will be months before she has any to offer to teens in her state. 

In the meantime, genetic testing has shown that the variants are already circulating there.

“We really want parents and family members who are eligible to be vaccinated because that is a great way to protect children that I cannot vaccinate yet,” Sato said. “The best way for me to protect children is to prevent the adults around them from being infected.”

Créditos: Comité científico Covid