Why Does COVID-19 Seem to Spare Children?

Vanderbilt University Medical Center study offers an answer

Newswise — Researchers at Vanderbilt University Medical Center (VUMC) and their colleagues have determined a key factor as to why COVID-19 appears to infect and sicken adults and older people preferentially while seeming to spare younger children. 

Children have lower levels of an enzyme/co-receptor that SARS-CoV-2, the RNA virus that causes COVID-19, needs to invade airway epithelial cells in the lung. 

The findings, published today<Nov 12> in the Journal of Clinical Investigation, support efforts to block the enzyme to potentially treat or prevent COVID-19 in older people. 

“Our study provides a biologic rationale for why particularly infants and very young children seem to be less likely to either get infected or to have severe disease symptoms,” said Jennifer Sucre, MD, assistant professor of Pediatrics (Neonatology), who led the research with Jonathan Kropski, MD, assistant professor of Medicine. 

Sucre and Kropski are co-corresponding authors of the paper. Bryce Schuler, MD, PhD, a resident in Pediatrics and Genetics at VUMC and postdoctoral fellow in the Vanderbilt Stimulating Access to Research in Residency program, is the paper’s first author.

There is still much to learn about SARS-CoV-2. But this much is known: After a viral particle is inhaled into the lungs, protein “spikes” that stick out like nail studs in a soccer ball attach to ACE2, a receptor on the surfaces of certain lung cells. 

A cellular enzyme called TMPRSS2 chops up the spike protein, enabling the virus to fuse into the cell membrane and “break into” the cell. Once inside, the virus hijacks the cell’s genetic machinery to make copies of its RNA. 

Sucre and Kropski, who have collaborated since 2016 on studies of lung diseases in premature infants and adults, wondered if TMPRSS2 had something to do with the greater severity of COVID-19 symptoms observed in older people compared to children. 

“Our research has always focused on understanding lung development and how infant lungs differ from adult lungs in their vulnerability to injury,” Sucre said. “In this study we actually took the opposite approach, and were able to see how the developing lung by its differences is protected from SARS-CoV-2 infection.” 

The researchers were well equipped to begin such a study. As members of the international Human Cell Atlas (HCA) Lung Biological Network, they and their colleagues had built a dataset on lung development in the mouse using a technique called single-cell RNA-sequencing. 

The technique can detect the expression of genes in individual cells of tissues such as the lung. In this way the researchers were able to track the expression of genes known to be involved in the body’s response to COVID-19 over time. 

They found that while the gene for ACE2 was expressed at low levels in the mouse lung, “TMPRSS2 stood out as having a really striking trajectory of increased expression during development,” Schuler said. 

With the help of VUMC pathologists, the researchers obtained and analyzed human lung specimens collected from donors of different ages, and confirmed a similar trajectory in TMPRSS2 expression to what they’d found in mice. 

“What we found is that expression of (TMPRSS2) goes up significantly with aging, and we see that at the level of the gene and at the level of the protein,” Sucre said. “We see a lot more TMPRSS2 in older individuals, in both humans and mice.” 

The researchers also used fluorescent probes to analyze autopsy specimens from three patients who died of COVID-19, and found the virus in three types of cells that express TMPRSS2

TMPRSS2 is well known for its role in the development of prostate cancer. Drugs that block the enzyme and which have been approved for the treatment of advanced prostate cancer currently are being tested clinically as potential treatments for COVID-19. 

The new findings reported today support further investigation. 

“We do think TMPRSS2 could be an attractive target both in treatment and potentially as a prophylaxis for (preventing infection in) people at high risk of COVID exposure,” Sucre said. 

The research was supported by grants from the National Institutes of Health.




Filters close

Showing results

110 of 5391
Released: 13-Apr-2021 4:05 PM EDT
B.1.1.7. variant more transmissible, does not increase severity, Lancet studies suggest
Lancet

An observational study of patients in London hospitals suggests that the B.1.1.7. variant is not associated with more severe illness and death, but appears to lead to higher viral load, consistent with emerging evidence that this lineage is more transmissible than the original COVID-19 strain.

Newswise: Plasma device designed for consumers can quickly disinfect surfaces
Released: 13-Apr-2021 3:05 PM EDT
Plasma device designed for consumers can quickly disinfect surfaces
Princeton Plasma Physics Laboratory

The COVID-19 pandemic has cast a harsh light on the urgent need for quick and easy techniques to sanitize and disinfect everyday high-touch objects such as doorknobs, pens, pencils, and personal protective gear worn to keep infections from spreading.

Newswise: Narratives Can Help Science Counter Misinformation on Vaccines
Released: 13-Apr-2021 12:50 PM EDT
Narratives Can Help Science Counter Misinformation on Vaccines
Iowa State University

Narratives are a powerful tool that can help explain complex issues, but they can also serve as sources of misinformation, which presents a challenge as public health agencies work to educate people about COVID-19 vaccine.

Released: 13-Apr-2021 10:05 AM EDT
Puerto Rico, Coronavirus Among Top Latino Twitter Topics During 2020 Election
George Washington University

Latinos discussed Puerto Rico and the COVID-19 pandemic more than any other subject on Twitter in the run-up to the 2020 election, according to researchers at the George Washington University. Spanish-language tweets mentioning “freedom” and “socialism” were also popular, while topics such as Obamacare and immigration did not gain much traction.

Newswise: Americans continue struggling for a good night’s sleep during the pandemic
Released: 13-Apr-2021 9:00 AM EDT
Americans continue struggling for a good night’s sleep during the pandemic
American Academy of Sleep Medicine (AASM)

The coronavirus pandemic continues to have a negative impact on our sleep, according to new findings from the American Academy of Sleep Medicine.

Newswise:Video Embedded the-science-behind-the-shot-biotech-tools-developed-at-brookhaven-lab-fundamental-to-making-covid-19-vaccines
VIDEO
Released: 13-Apr-2021 8:05 AM EDT
The Science Behind the Shot: Biotech Tools Developed at Brookhaven Lab Fundamental to Making COVID-19 Vaccines
Brookhaven National Laboratory

You’ve probably heard that the first two vaccines approved for battling COVID-19 in the United States use a relatively new approach—injections of simple packets containing mRNA, a genetic material that instructs our cells to make coronavirus spike proteins. But the technology for generating sufficient amounts of those mRNA packets dates back to the 1980s, when F. William Studier, then a senior biophysicist at the U.S. Department of Energy’s Brookhaven National Laboratory, developed a way to harness the molecular machinery of a very different virus.

Newswise: UCLA Fielding School of Public Health Scholar’s Work on Fatigue and Health Published
Released: 13-Apr-2021 4:05 AM EDT
UCLA Fielding School of Public Health Scholar’s Work on Fatigue and Health Published
UCLA Fielding School of Public Health

A landmark work has been published examining fatigue as a hugely important factor in human health and extremely relevant to those with “long-haul” COVID-19 symptoms.

access_time Embargo lifts in 2 days
Embargo will expire: 14-Apr-2021 2:00 PM EDT Released to reporters: 12-Apr-2021 4:05 PM EDT

A reporter's PressPass is required to access this story until the embargo expires on 14-Apr-2021 2:00 PM EDT The Newswise PressPass gives verified journalists access to embargoed stories. Please log in to complete a presspass application. If you have not yet registered, please Register. When you fill out the registration form, please identify yourself as a reporter in order to advance to the presspass application form.


Showing results

110 of 5391

close
6.13107