Unvaccinated teens in L.A. are more likely to test positive for coronavirus than adults

A masked worker fills a syringe with COVID-19 vaccine
June Paulo Allida fills a syringe with COVID-19 vaccine at a skid row vaccination clinic on Aug. 4.
(Francine Orr / Los Angeles Times)

Unvaccinated teenagers have been more likely to test positive for the coronavirus than unvaccinated adults in Los Angeles County, officials said.

The trend illustrates how a group less likely to have been vaccinated in the nation’s most populous county is playing an outsize role in continuing transmission of the highly contagious Delta variant.

“The highest case rates have been among unvaccinated teens, who were eight times more likely than vaccinated teens to test positive for COVID and are important drivers of transmission across our communities,” L.A. County Public Health Director Barbara Ferrer said in a recent briefing.

Previously, health officials had noted that it was younger adults who were most likely to contract the coronavirus.

But the possibilities for contracting the coronavirus have climbed as social gatherings and extracurricular activities for teenagers have resumed. L.A. County’s unvaccinated youths ages 12 to 17 have a monthly coronavirus case rate 32% worse than that of unvaccinated residents younger than 50, according to data collected between Sept. 16 and Oct. 15.


Not coincidentally, it’s young L.A. County residents who are least likely to be vaccinated. While 80% of L.A. County residents eligible for vaccination have received at least one shot, only 70% of 12- to 15-year-olds have done so, as have 76% of those age 16 to 17. By comparison, 98% of residents age 65 to 79 have received at least one shot.

Even though all high-school-age residents have been eligible for the vaccine since May, the relatively high proportion of unvaccinated teens is contributing to reported outbreaks in L.A. County’s schools. Of nearly 1,000 coronavirus cases linked to outbreaks in K-12 schools since August, nearly half were related to youth sports, and all but one of the 21 outbreaks tied to such activities were among high school students.

“Outbreaks among youth sports teams and high schools result in a lot more transmission,” Ferrer said.

Relatively high coronavirus case rates among teens are only more reason to get them and other children vaccinated when they become eligible, said Dr. George Rutherford, an epidemiologist and infectious-disease expert at UC San Francisco. Coronavirus transmission rates in much of California are still “substantial” or “high,” the worst two categories in the U.S. Centers for Disease Control and Prevention’s four-tier scale.


“The chances of becoming infected are real,” said Rutherford, who is also a board-certified pediatrician. “And that’s because not everybody’s vaccinated.”

This is true even in California’s most highly vaccinated counties. In the San Francisco Bay Area, more than 20% of people of all ages are not fully vaccinated; in L.A. and Orange counties, more than 30% are not fully vaccinated, and “that’s plenty to sustain transmission,” Rutherford said.

“This is not a disease that you want to have in childhood or in adulthood. You just don’t want to have it, period,” Rutherford said. “While this epidemic is at full tilt, you need to protect your kids as best as you can. And vaccination is a very important way to do that.”

California has stopped recording week-over-week declines in coronavirus cases and COVID-19 hospitalizations.

Oct. 30, 2021

According to the CDC, 791 people under age 18 have died from COVID-19 nationwide, and more than 5.4 million have tested positive for the coronavirus. The American Academy of Pediatrics says that at least 24,000 children have been hospitalized for COVID-19 since the start of the pandemic in 24 states and New York City, which release data on hospitalizations by age group.

There is one significant post-vaccination side effect that officials have been monitoring: myocarditis, an inflammation of the heart.


There have been rare instances of the condition following vaccination, notably among males age 12 to 17. A clinical trial involving a few thousand 5- to 11-year-olds found no reports of myocarditis among those who received the Pfizer vaccine, but because the trial was relatively small, more monitoring will be needed to determine whether post-vaccination myocarditis will end up emerging as the vaccine is distributed more broadly.

Available data show that getting myocarditis from the vaccine is much less likely than getting it from COVID-19, Rutherford said.

Rutherford also cited data showing that among children younger than 16 who had contact with hospitals from March 2020 to January 2021, those suffering from COVID-19 were 36.8 times more likely to suffer from myocarditis than those who did not have COVID-19.

The overall risk for kids is small, but COVID has become a leading cause of death for children, making vaccination as important as ever, experts say.

Oct. 27, 2021

The CDC says that as of Oct. 20, federal agencies had confirmed 963 reports of myocarditis among vaccinated people age 30 and younger, most commonly among those who got either the Pfizer or Moderna vaccine, particularly in males. Those low numbers indicate that post-vaccination myocarditis is rare, and other data suggest that even when it does happen, it appears to be far more benign than other forms of myocarditis, Rutherford said, and goes away quickly with rest.

The median length of hospitalization is six days for COVID-19 and one day for vaccine-related myocarditis, according to the U.S. Food and Drug Administration.

“Vaccine-associated myocarditis is less severe, and patients recover quickly without intervention. So, yes, I think the calculus for vaccination is far, far in favor of vaccinating, and I strongly recommend it,” Rutherford said.

Of six scenarios considered by the FDA of the potential benefits and risks of the vaccine for those age 5 to 11, five clearly showed that vaccinations result in the benefit of more children avoiding hospitalization from COVID-19 than might potentially contract post-vaccine myocarditis.


The one scenario that was debatable involved a projection that COVID-19 hospitalizations would fall to very low levels — just 10% of what was reported in mid-September. In that scenario, the model found that vaccinations would cause more cases of vaccine-related myocarditis than would avert hospitalizations due to COVID-19.

However, even in that scenario, when one considers how COVID-19 hospitalization in children causes far more severe illness than vaccine-related myocarditis, “the overall benefits of the vaccine may still outweigh the risks,” Hong Yang, a senior advisor for benefit-risk assessment for the FDA, told an advisory committee to the agency.

Rutherford said the assumptions in that scenario — that hospitalizations would fall to a very low level — are unlikely to occur in the near future. “I find that preposterous,” he said.

For the scenarios that he considered more plausible, “the risk of myocarditis from naturally acquired infection is higher than the rare risk from vaccine.”

Children in California ages 5 to 11 could be able to get their first dose of the Pfizer COVID-19 vaccine by the middle of next week.

Oct. 28, 2021

Children who get infected with the coronavirus also have a rare risk of developing a serious condition that usually requires hospitalization. Of children who are hospitalized for the rare COVID-related condition Multisystem Inflammatory Syndrome in Children, or MIS-C, preliminary data suggest that 8% to 9% are diagnosed with myocarditis.

Nationally, there have been 5,217 reports of MIS-C, 46 of which have resulted in death. In California, there have been 677 reports of MIS-C, six of which have resulted in death. Between 60% and 70% of patients with MIS-C require intensive care.


Some experts were hopeful that the lowered vaccination dosage for young children, who will be given one-third as much vaccine as those 12 and older, will reduce the chance of side effects like post-vaccination myocarditis.

Dr. Regina Chinsio-Kwong, a deputy health officer for Orange County, concurred that post-vaccination myocarditis, when it happens, usually results in minor symptoms that last only a couple of days and can be treated with Motrin.

Chinsio-Kwong said she is far more worried about the long-term health consequences should unvaccinated children get COVID-19.

“My concern is that you would be looking at a more severe impact on your heart and your cardiovascular system that would have more long-term consequences,” Chinsio-Kwong said.

It’s those kinds of concerns that caused her to get one of her sons vaccinated as soon as the Pfizer vaccine was eligible for him, and why she is eager to get a younger son vaccinated as soon as he becomes eligible.

“The last thing I want is for any of my kids to get COVID,” Chinsio-Kwong said. “When you hear from the pediatricians of the Multisystem Inflammatory Syndrome that can occur months after exposure to COVID, it is very scary. We want our children to really do well.”


Chinsio-Kwong said there is concern that some children who have survived COVID-19 have higher rates of depression or anxiety, difficulty concentrating in school or long-term headaches.

“There’s obviously many other consequences that can occur beyond the COVID infection itself. And we really don’t know how long that affects that child — if it goes all the way to their adulthood,” Chinsio-Kwong said.

Federal health officials aren’t giving any specific recommendations, but there are options for COVID-19 boosters, and it’s OK if you mix vaccines.

Oct. 31, 2021

Illness that lasts a month or more after a coronavirus infection — known as long COVID — can happen in children. A study recently published in the journal Lancet Child and Adolescent Health said that among more than 1,700 British children age 5 to 17 with symptomatic COVID, 4.4% had symptoms that persisted for 28 days or more, and 1.8% had symptoms that persisted for at least 56 days. Common long COVID symptoms included headache and fatigue.

Vaccinations reduce the likelihood not only of coming down with COVID-19 but of suffering from long COVID, Dr. Anthony Fauci, the U.S. government’s top infectious-disease expert, said recently. Fauci cited a study in the journal Lancet Infectious Diseases that said that fully vaccinated people were half as likely as unvaccinated people to report long COVID symptoms.

State officials are preparing to offer COVID-19 vaccine doses to California’s 3.5 million children ages 5 to 11 as soon as the end of next week.

Oct. 27, 2021

Dr. Robert Wachter, chair of UC San Francisco’s Department of Medicine, said allowing a population of kids to remain unvaccinated only increases the probability of ongoing coronavirus spread.

Wachter said we cannot count on COVID-19 disappearing any time soon, and we’re likely to enter into a state of relatively stable, and fairly high, levels of infection.


“There are simply too many unvaccinated people, too many regions where precautions are out the window, and then you have waning immunity from both vaccination and from natural infection — all of this makes counting on COVID going away a fool’s errand,” Wachter wrote in an email. “It’ll be with us, and so the justification for childhood vaccination will remain robust.”

Officials say it’s possible to safely participate in many holiday activities if everyone is vaccinated for COVID. But extra precautions may be needed.

Oct. 20, 2021

Shane Crotty, a professor at the La Jolla Institute of Immunology, said in a tweet that if he had children age 5 to 11, he would get them the Pfizer vaccine as soon as they became eligible.

Crotty, too, wrote that the myocarditis associated with vaccination is transient and mild, with most patients hospitalized for observation, rather than treatment. “So, not super concerning, compared to viral infection myocarditis which can have severe long term consequences,” Crotty wrote.

More evidence shows that vaccinations can offer better protection against COVID-19 than natural immunity from a prior infection.

Oct. 29, 2021

Meanwhile, Dr. Seira Kurian, interim regional health officer for the L.A. County Department of Public Health, said it is important that children who have survived a coronavirus infection get vaccinated.


“Based on what we know so far, the immunity that we receive from natural infection may not be as stable as immunity that we receive from vaccination,” Kurian said. “The immunity that you receive from vaccination provides you a much more robust and consistent protection than natural immunity alone does.”