Studies reveal sharp increase in COVID-19 in kids, and variations in the virus

March 5, 2020

COVID-19 has become endemic to the Chinese city of Shenzhen, and a sharp increase in pediatric infections may indicate that community and intra-family transmissions have become the new mode of spreading the virus, according to a study published in Emerging Infectious Diseases.

Also, in a research letter published in the Journal of Infection, researchers described and compared the wide range and changing characteristics of COVID-19 infection on computed tomographic (CT) imaging with clinical manifestations to improve diagnosis. The CT study found that COVID-19 has a variety of manifestations. The false negative rate of oropharyngeal swabs seems high. Currently, oropharyngeal swabs are the recommended upper respiratory tract specimen types for SARS-CoV-2 diagnostic testing so the researchers recommend that a new detection technique should be developed as soon as possible.

Led by researchers at the Third People's Hospital in Shenzhen, their study analyzed clinical and epidemiologic characteristics of the city’s first 365 COVID-19 patients with laboratory-confirmed disease, including 74 clusters of 183 cases. The median patient age was 46 years (range, 1 to 86 years), and the cases were split evenly between males and females.

To investigate the shift of the epidemic, the researchers compared patient characteristics before Jan 24 with those from Jan 25 to Feb 5. “Compared with before Jan 24, the proportion of case-patients without definite exposure was much higher from Jan 25 through Feb 5 (11% vs. 6%) and increased to 36% (12/33) on both Jan 31 and Feb 5,” the authors wrote.

They also reported a sharp increase in the proportion of infected children (2% before Jan 24 to 13% for Jan 25 to Feb 5), meaning that increased exposure for children and familial transmission could contribute substantially to the epidemic.

The researchers noted that the steep increase could be attributed to the low proportion of children exposed early in the outbreak; early detection for children who had had close contact with people with diagnosed or suspected infection after control measures were implemented; or failure to identify the relatively mild signs and symptoms in children, especially because resources were limited early in the Wuhan outbreak. The investigators caution that delays from infection to illness onset or onset to confirmation may have biased the comparisons.

Of 56 clusters of single co-exposure cases, the mean interval of symptom onset between the primary and second case-patient in a cluster was 3.1 days. The mean interval of symptom onset between the primary and last case-patient within a cluster was 3.6 days.

After strict control measures were implemented, the researchers observed a shortened span from illness onset to hospital visits (median days declined from 3 to 1).

The investigators recommend that infected patients be treated at designated hospitals to decrease the risk of nosocomial transmission. However, they found that only 13% to 15% of infected patients went to the city's designated hospital first. "This finding means that a substantial number of case-patients visited >1 nondesignated hospital before they were admitted to the designated hospital, which increases the risk for nosocomial infection," they wrote.

"Early screening, diagnosis, isolation, and treatment are necessary to prevent further spread," the researchers wrote. "Strengthening effective and efficient measures, including but not limited to personal protection within families and communities with a high risk for exposure, will prevent and interrupt community and intrafamily transmission."

In other research news, pregnant women are not at increased risk of having severe symptoms of COVID-19 infection, according to an analysis of 147 women in Wuhan published by the World Health Organization and China. The analysis found that only 8% of the women had serious illness, and 1% were critically ill.

This is in contrast to other respiratory infections that easily infect pregnant women and can cause serious illness, with long-lasting consequences for them and their babies.

While long-term effects on the babies are unknown, a small study published in February in The Lancet showed that the newborns of women infected with COVID-19 appeared healthy and virus-free after cesarean delivery and isolation from their mothers.

CIDRAP has the story.

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