TORONTO -- A new study has found that the majority of children infected with COVID-19 may not show typical symptoms including fever, cough or shortness of breath.

As a result, the study's authors say more vigilance is needed when screening children for SARS-CoV-2, the virus that causes COVID-19.

The study, conducted by researchers out of the University of Alabama at Birmingham (UAB), also found that children with COVID-19 may develop poor clinical outcomes such as hospitalization and mechanical ventilation.

"While the rates of poor clinical outcomes are relatively lower in children when compared to adults, 5-6 per cent still required hospitalization. Among those hospitalized, 18 per cent required critical care and 4 per cent needed a ventilator for breathing," Vibhu Parcha, a clinical research fellow at UAB and the study's lead author, said in a press release.

The findings were published Thursday in peer-reviewed journal Scientific Reports.

The study comes after Health Canada and the U.S. Food and Drug Administration recently approved the Pfizer-BioNTech COVID-19 vaccine for use in children aged 12 and older.

UAB researchers examined data on 12,306 pediatric patients with laboratory-confirmed COVID-19 across the U.S.

The study reported that 18.8 per cent of these children had symptoms such as fever, malaise, muscle or joint pain, and disturbances of smell or taste, while 16.5 per cent had respiratory symptoms including cough and shortness of breath.

The study also found that 13.9 per cent of children had gastrointestinal symptoms such as nausea, vomiting and diarrhea, 8.1 per cent had dermatological symptoms including rashes, and 4.8 per cent suffered from headaches.

Researchers reported that non-Hispanic Black children and Hispanic children with COVID-19 had a higher risk of hospitalization compared to those who are white.

However, they noted that the risk of requiring critical care or mechanical ventilation was similar among children from all racial backgrounds. Researchers said the risk of hospitalization was also similar among gender.

Due to a lack of available data, researchers say they were unable to outline the duration of hospitalization for those children affected.

Senior author of the study Pankaj Arora, a physician-scientist in UAB's Division of Cardiovascular Disease, said racial disparity should be taken into consideration when prioritizing vaccinations for children.

"As vaccinations become available to teenagers, we need to ensure that we make the vaccine available to all eligible children, especially those from minority populations and high-risk households," Arora said in the release.

While the study's findings suggest that children and adolescents with COVID-19 may have a milder course of illness than adults, Arora says vigilance is still necessary as schools work to reopen.

"A key takeaway from this study is children with COVID-19 require enhanced screening and preventive measures that include low threshold for screening, ease of access to testing facilities and vaccination of eligible teenagers," Arora said.

He added that these strategies may need to be enhanced among children from racial minorities to reduce the "existing COVID-19 related health disparities."