Understanding how COVID-19 affects children vital to slowing pandemic

March 19, 2020

Science Daily/University of Virginia Health System

Though COVID-19 so far appears to be largely sparing children, researchers are cautioning that it is critical to understand how the virus affects kids to model the pandemic accurately, limit the disease's spread and ensure the youngest patients get the care they need.The warning comes from Steven L. Zeichner, MD, PhD, the head of UVA Health's Division of Pediatric Infectious Diseases, and Andrea T. Cruz, MD, MPH, a pediatric emergency medicine physician at Houston's Baylor College of Medicine. They have authored a commentary in the journal Pediatrics accompanying a new article that reveals a small percentage of infected children become seriously ill. Those at greatest risk include babies and preschoolers.

"Many infectious diseases affect children differently than adults and understanding those differences can yield important insights," the commentary authors write. "This will likely be true for COVID-19, just as it was for older infectious diseases."

Assessing COVID-19 Risks

Zeichner and Cruz note that there are subgroups of children who appear to be at greater risk of COVID-19 complications, particularly those who are younger, immunocompromised or have other pulmonary health problems.

However, the presence of other viral infections in up to two-thirds of childhood coronavirus cases makes it very difficult to assess the true effect of COVID-19 on children, they state. (This figure is based on prior studies of children with coronaviruses detectable in the respiratory tract.)

While much remains unknown, Cruz and Zeichner caution that children, even asymptomatic children, could play a "major role" in disease transmission. For example, they cite a study that found the virus remained in children's stool for several weeks after diagnosis. That, combined with other routes of transmission such as nasal secretions, could pose a major challenge for schools, day care centers and the children's families, they note.

"Since many children infected with COVID-19 appear to have have mild symptoms, or even no symptoms at all, it is important to practice all the social distancing, hygiene and other precautions being recommended by public health authorities to minimize transmission from children to others, including family members who may be at greater risk from the infection, such as grandparents or family members with chronic medical conditions," said Zeichner, who is working on innovative potential COVID-19 vaccines in his lab. "In addition, studies of the reasons why children are affected differently than adults by the infection may yield insights that can be helpful in understanding the disease and ways to treat or prevent it."

https://www.sciencedaily.com/releases/2020/03/200319125201.htm

COVID-19 appears less severe in children

March 13, 2020

Science Daily/Wolters Kluwer Health

As outbreaks of COVID-19 disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue worldwide, there's reassuring evidence that children have fewer symptoms and less severe disease. That's among the insights provided by an expert review in The Pediatric Infectious Disease Journal, the official journal of The European Society for Paediatric Infectious Diseases. The journal is published in the Lippincott portfolio by Wolters Kluwer.

Like previous epidemic coronaviruses, "SARS-CoV-2 [seems] to cause fewer symptoms and less severe disease in children compared with adults," according to the review by Petra Zimmerman, MD, PhD, of the University of Fribourg, Switzerland and Nigel Curtis, FRCPCH, PhD, of The University of Melbourne, Australia. They summarize available evidence on coronavirus infections in children, including COVID-19.

"There is some suggestion that children are just as likely as adults to become infected with the virus but are less likely to be unwell or develop severe symptoms," Drs. Zimmerman and Curtis write. "However, the importance of children in transmitting the virus remains uncertain."

The Evidence on SARS-CoV-2 -- Focusing on Risks to Children

Coronaviruses are a large family of viruses that can cause infection and disease in animals. "Coronaviruses are capable of rapid mutation and recombination, leading to novel coronaviruses that can spread from animals to humans," Drs. Zimmerman and Curtis write. There are four coronaviruses that circulate in humans, mostly causing respiratory and gastrointestinal symptoms -- ranging from the common cold to severe disease.

Over the past two decades, there have been three major disease outbreaks due to novel coronaviruses: SARS-CoV in 2002, MERS-CoV in 2012, and now SARS-CoV-2 in 2019. Arising in the Chinese city of Wuhan, SARS-Cov-2 spread rapidly around the world and has been declared a pandemic by the World Health Organization. "The term COVID-19 is used for the clinical disease caused by SARS-CoV-2," according to the authors. Transmission of SARS-CoV-2 appears similar to that of the related SARS and MERS coronaviruses, but with a lower fatality rate. SARS-CoV-2 can still cause serious and life-threatening infections -- particularly in older people and those with pre-existing health conditions.

What are the risks for children from SARS-CoV-2? It's a pressing question for pediatric infectious disease specialists and concerned parents alike. Children appear to have milder clinical symptoms than adults and to be at substantially lower risk of severe disease -- which was also true in the SARS and MERS epidemics.

In Chinese data from February 2020, children and adolescents accounted for only two percent of SARS-CoV-2 hospitalizations, Drs. Zimmerman and Curtis write. However, as children are less frequently symptomatic and have less severe symptoms they are less often tested, which might lead to an underestimate of the true numbers infected. Also, children are less frequently exposed to the main sources of transmission.

Again based on Chinese data, "Most infected children recover one to two weeks after the onset of symptoms, and no deaths had been reported by February 2020," the researchers add. Most reported infections with SARS-CoV-2 have occurred in children with a documented household contact. Children with COVID-19 may be more likely to develop gastrointestinal symptoms.

The experts also review the diagnostic findings (laboratory tests and imaging studies) of children with COVID-19 laboratory and imaging findings in children. Whole genome sequencing approaches have enabled rapid development of molecular diagnostic tests for SARS-CoV-2. For now, treatment is supportive; no specific antiviral medications are available.

Several approaches are being considered for development of new drugs and vaccines -- some targeting a "spike glycoprotein" involved in interactions between coronaviruses and cells. Until such treatment and preventive measures are available, the researchers emphasize the importance of the full range of strategies for controlling SARS-CoV-2 -- as for the "highly effective global public health response" that led to containment of the SARS epidemic.

https://www.sciencedaily.com/releases/2020/03/200313112145.htm