As schools reopen, scientists say some children could spread COVID-19 even if they already have the antibodies


As schools and colleges reopen across the country, scientists say social distancing remains a critical public-health response to COVID-19. New research released Thursday sheds more light on children who test positive for COVID-19, and the contagiousness of coronavirus. Children often remain asymptomatic or display very few symptoms, and the research also offers insights into the course of the disease at an important time for families and communities.

A study published in the latest edition of the Journal of Pediatrics finds that the virus and antibodies can coexist in young patients. “With most viruses, when you start to detect antibodies, you won’t detect the virus anymore. But with COVID-19, we’re seeing both,” says Burak Bahar, lead author of the study and director of Laboratory Informatics at Children’s National Hospital in Washington, D.C. “This means children still have the potential to transmit the virus even if antibodies are detected.”


‘Children still have the potential to transmit the virus even if antibodies are detected.’


— Burak Bahar, director of Laboratory Informatics at Children’s National Hospital in Washington, D.C.

The researchers reviewed an analysis of 6,369 children tested for SARS-CoV-2, the virus that causes COVID-19, and 215 patients who underwent antibody testing at Children’s National between March 2020 and June 2020. Out of these 215 young patients, 33 tested positive for both the virus and antibodies during the course of the disease. Nine of those 33 also showed presence of antibodies in their blood while also later testing positive for the virus.

What’s more, researchers found that patients aged 6 years through 15 years old took a longer time (a median time of 32 days) to clear the virus, meaning that it had left their systems, versus patients aged 16 years through 22 years old (a median of 18 days). Females in the 6 to 15 age group also took longer to clear the virus than males: A median of 44 days for females versus 25.5 days for males. “We can’t let our guard down just because a child has antibodies or is no longer showing symptoms,” Bahar said.

The study also found that 25 days was the median time from viral positivity to negativity — the moment when the virus can no longer be detected; it took 18 days to go from viral positivity to seropositivity — or the presence of antibodies in the blood — and it took 36 days to reach adequate levels of neutralizing antibodies. These “neutralizing antibodies” are important in potentially protecting a person from reinfection of the same virus, the researchers wrote.

Four important caveats: Firstly, the study looked at a relatively small number of children. Secondly, the next phase of research will be to test whether coronavirus that is present along with the antibodies for the disease can be transmitted to other people. Thirdly, scientists need to explore whether antibodies correlate with immunity and, fourthly, they need to establish how long antibodies and potential protection from reinfection actually lasts. As such, Bahar reiterates the need for social distancing.

Related:Dr. Fauci: It’s ‘conceivable’ we’ll know by November if a safe, effective vaccine is coming

A separate study published this week in JAMA Pediatrics suggests that children can spread SARS-CoV-2, even if they never develop symptoms or even long after symptoms have cleared. It found a significant variation in how long children continued to “shed” the virus through their respiratory tract and, therefore, could potentially remain infectious. The researchers also found that the duration of COVID-19 symptoms also varied widely, from three days to nearly three weeks.

A recent systematic review estimated that 16% of children with a SARS-CoV-2 infection are asymptomatic, but evidence suggests that as many as 45% of pediatric infections are asymptomatic, according to the U. S. Centers for Disease Control and Prevention. The signs and symptoms of COVID-19 in children are similar to other infections and noninfectious processes, including influenza, according to the CDC.


A separate study in JAMA Pediatrics said children may spread SARS-CoV-2, even if they never develop symptoms or even long after symptoms have cleared.

Under pressure from the teachers union to delay the start of the school year, New York City Mayor Bill de Blasio announced Tuesday that in-person classes will be pushed back until Sept. 21, 11 days later than planned. Remote learning, also originally slated to start on Sept. 10, will now commence on Sept. 16. Other countries have not fared so well with school reopenings. Israel, which also reopened schools this week, experienced outbreaks when it reopened schools on May 17.

Bahar also advised teachers and students to wear masks. To reduce the risk of spreading COVID-19, it may be preferable to use high-quality cloth or surgical masks that are of a plain design instead of face shields and masks equipped with exhale valves, according to an experiment published Wednesday by Physics of Fluids, a monthly peer-reviewed scientific journal covering fluid dynamics that was first established by the American Institute of Physics in 1958.

As of Sunday, the U.S. still has the world’s highest number of COVID-19 cases (6,262,989), followed by Brazil (4,123,000), India (4,113,811) and Russia (1,022,228), according to data aggregated by Johns Hopkins University. California became the first state in the country to surpass 700,000 confirmed cases. COVID has killed 188,711 people in the U.S. Worldwide, cases are near 27 million.

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, in combination with Oxford University; BioNTech SE
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and partner Pfizer
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; GlaxoSmithKline
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; Johnson & Johnson
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; Merck & Co.
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are among those currently working toward COVID-19 vaccines.

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Testing for COVID-19 antibodies could be a ‘game-changer’ for the economy but it’s still too early to tell


Some government officials and researchers are pinning their hopes for an economic recovery on the creation and widespread utilization of antibody tests that can identify who has immunity to COVID-19.

People who contract the novel coronavirus report varying degrees of illness; some are asymptomatic, others are sick but able to recover at home on their own, and about one-fifth are severely ill enough to be hospitalized. For the individuals who are asymptomatic or those who do recover, a serological test that can identify COVID-19 antibodies could allow them to return to work or reduce the level of social and economic lockdown restrictions that many Americans face today.

“This would be a game-changer in restarting parts of the economy more quickly and safely,” Dr. Harvey Fineberg, a professor in the Harvard T.H. Chan School of Public Health, wrote in an April 1 editorial in the New England Journal of Medicine.

Read: How healthy are not-for-profit hospitals amid the coronavirus pandemic?

The Food and Drug Administration (FDA) has said there are two use cases for serological tests: they could one day help decide whether people can return to work, and they could identify who has recovered to see if they can donate plasma that may be used as a treatment for people with severe forms of the disease caused by the novel coronavirus.

In the U.S., more than 402,000 people have tested positive for COVID-19 and at least 13,000 have died, according to data aggregated by Johns Hopkins University.

“We think it will be a tool to help us get people back to work,” FDA commissioner Dr. Stephen Hahn said Saturday during a press briefing. “It’ll be additional information because, as you know, if you have an antibody, that means you are exposed and have recovered from it. That, with the information about diagnosis, should help.”

A growing chorus of political leaders, both in the U.S. and abroad, have started to talk about how widespread antibody testing could help restart economies that have all but been halted by the arrival of the virus in their communities. The testing has been mentioned by a handful of U.S. governors, Trump administration officials, and leaders in the U.K. and Canada over the past week. In Singapore, which has 1,623 cases and only six deaths, health officials have been using a serology test since late February, according to Science.

“The serological tests are also something that is being looked at very, very carefully,” Canadian Prime Minister Justin Trudeau said Tuesday. “We [are] still in the early days of reflecting, not just on the medical implications but on the societal implications of those tests as well.”

See also: U.S. was not adequately prepared for pandemic, says J.P. Morgan CEO Jamie Dimon

Only one antibody test has received emergency use authorization in the U.S., according to the FDA. (As part of the administration’s response to the pandemic, the FDA is using its emergency powers to grant temporary authorizations to certain tests and treatments given the lack of alternative options for COVID-19. An EUA doesn’t indicate that the FDA approved or cleared the therapy or test.)

That company is Cellex Inc., a privately held company with research operations in Research Triangle Park, N.C. Separately, Stanford Medicine is running a project testing volunteers in California’s Santa Clara County to see if they have been exposed to the virus, with a goal of obtaining FDA authorization for its serologic test, a spokeswoman said by email. The Centers for Disease Control and Prevention has also said it is building a serological test, while New York Gov. Andrew Cuomo said this week that the state’s health department had developed an antibody testing regimen that will seek FDA authorization.

The FDA said Tuesday that more than 70 companies have told the agency that they have serological tests; however, some companies are reportedly claiming their tests are approved, authorized or can diagnose COVID-19 when they are not or cannot.

That said, questions about fraudulent tests aren’t the only concern when it comes to serological testing. Other experts have raised questions about the downstream effects of tests that are sometimes inaccurate as well as the feasibility of testing many millions of people. So far, the U.S. has conducted a total of 1.7 million tests to diagnose COVID-19, counting tests performed by both public and private laboratories, in a population of roughly 330 million.

Cuomo has talked up the potential to allow people in New York to return to work or school but also acknowledged the challenges within that process. “You have to have that testing on a scale, right?” he said during a news conference. “You have 19 million people in the state of New York. Just think of how many people you would need to be able to test and test quickly.”

See also: Blacks, Latinos in NYC disproportionately fall victim to coronavirus

Last week, Evercore ISI’s Josh Schimmer argued that a serological testing-based strategy to free up the workforce isn’t practical — the best test he’s seen so far has 90% sensitivity, meaning it is not 100% accurate in detecting the presence or lack thereof of antibodies.

“Can you imagine if it turned out that 30% to 70% of patients who were told they have COVID immunity actually didn’t?” he wrote in an April 2 investor note.

However, not all analysts share that view.

“Mass antibody testing, assuming it becomes available with a sufficiently high accuracy rate from the end of this month or from the beginning of May in some countries, could help to identify immune individuals,” J.P. Morgan analysts wrote in a note on Tuesday. “Identifying these individuals and allowing them to return to work could facilitate the normalization process.”



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