PARENTS worry about sending their children back to school. Teachers are anxious about the risk of Covid-19 spreading in their schools. What do current publications say about Covid-19 infection in children? This column attempts to present an opinion that may change as more research gets published. Do consult your doctor familiar with your child’s health condition and family risk factors, especially the elderly and those with comorbidities – obesity, hypertension, diabetes.
Covid-19 infection in children below 19 years of age occurs less commonly and is milder than in adults, requiring less hospitalisation and intensive care.
About 29.3 per cent of the world population is under 18 years of age, yet only 1 to 5 per cent of all confirmed Covid-19 cases globally are children below 19 years (henceforth referred to as ‘children’ or ‘child’). This was the finding of a systematic review of 45 publications (Jan 1 to March 18, 2020).
A review of 23 government websites of the 70 countries with a minimum 1,000 Covid-19 cases by April 13, 2020, revealed 424,978 Covid-19 cases. Only 1.9 per cent were children. Combining data from the 23 websites and nine publications (with 4,251 cases in four additional countries) found that 14 per cent of infected children required admission and 7 per cent of the admitted children needed ICU. There were only 15 reported deaths in this large series of over 12,000 Covid-19 positive children.
The low hospitalisation rate for Covid-19 children corroborates with US statistics that less than 1 per cent of all US Covid-19 hospitalisations were children. Overall, adults aged over 65 account for 31 per cent of cases, 45 per cent of hospitalisations, 53 per cent of ICU admissions, and 80 per cent of deaths associated with Covid-19. Severe outcome was highest among persons over 85 years.
Malaysia to date has 317 Covid-19 children (3.7 per cent of total 8,572 cases) with no deaths. None were ventilated and a few needed oxygen via nasal prongs.
Mild symptoms, good prognosis
Most Covid-19 children present with mild symptoms, requiring supportive care only. Prognosis is typically good and they recover within one to two weeks. Deaths from Covid-19 in children is uncommon.
A review of 18 studies (Dec 1, 2019 to March 3, 2020) had 1,065 child cases and only one death (17 articles reflected research in China and one Singapore case report). No deaths were reported in the age range of zero to nine years. Only one death was reported in the age range of 10 to 19 years.
Most presented with mild respiratory symptoms, fever, dry cough, and fatigue or were asymptomatic. Bronchial thickening and ground-glass opacities on chest X-rays were the main radiologic features. These X-ray findings were also reported in some asymptomatic patients. Most paediatric patients were hospitalised. Symptomatic children received mainly supportive care. A 13-month-old presented with pneumonia, complicated by shock and kidney failure, and was successfully treated with intensive care.
Deaths uncommon in children
The China CDC Novel Coronavirus Pneumonia Emergency Response Epidemiology Team analysed 72,314 Covid-19 cases reported through to Feb 11, 2020. A total of 44,672 were positive by RT-PCR. Of these confirmed cases, only 2 per cent were children aged zero to 19 years. Only 0.9 per cent (416 cases) were below 10 years of age with no deaths. There was one death in the 10 to 19 years old group (549 cases). A total of 86.6 per cent of cases were 30 to 79 years old. Those older than 60 years were 31.2 per cent of total cases but contributed to 81 per cent of deaths.
Only 1.2 per cent of 22,512 Italian Covid-19 cases were children, with no deaths as of March 15. A total of 87.9 per cent of Italian deaths were aged above 70 years, who made up 37.6 per cent of total cases. No deaths were reported in anyone below the age of 30 years.
In the United States, of 4,226 Covid-19 cases detected from Feb 12 to March 16, only 5 per cent were children. As of April 2, 2020, there have been three deaths among children. Compared to adult patients, there were fewer children with Covid-19 requiring hospitalisation (6 to 20 per cent) and ICU admission (0.6 to 2 per cent).
In Germany, the Robert Koch Institute reported 174,355 Covid-19 cases as of May 17, 2020. Infected children 10 years and below made up 1.9 per cent, while 4.3 per cent were aged 10 to 19 years. Only three deaths occurred among those aged three to 18, all of whom had underlying conditions.
Infants below 12 months and children with underlying conditions – chronic lung disease (including asthma), cardiovascular disease, and immunosuppression – may be at higher risk of infection, severe disease, hospitalisation, and intensive care with Covid-19.
An increase in Kawasaki syndrome cases (multisystem inflammatory syndrome in children) linked to Covid-19 have been reported, and more information will no doubt be available in due course. Cases of Kawasaki (the cause of which is still unknown) have been seen in my paediatric practice pre-Covid. I have referred one to two cases a year for investigation and hospitalisation. So far, I have not seen any increase in cases.
Most Covid-19 cases in children mild
A total of 51 per cent of 2,143 paediatric patients with Covid-19 from China were reported to have mild symptoms (fever, fatigue, myalgia, cough), 4 per cent were asymptomatic. There have been multiple reports of children with asymptomatic Sars-CoV-2 infection, up to 13 per cent in one study. The role of such cases in Sars-CoV-2 transmission is still unknown.
Epidemiological investigations of clusters in community and families suggest that the transmission risks from infected child to others in the home or school seem to be low. Infected adults seem more likely to transmit the virus to children than the other way around.
An English tourist (infected from Singapore) stayed four days in the French Alps chalet with 10 English tourists and a family of five French residents. He infected five individuals in France, five in England, and one in Spain. One infected nine-year-old child visited three different schools while symptomatic. Not a single Covid-19 case was found among the child’s 172 contacts.
In the investigation of 18 Covid-19 cases (nine children, nine teachers) from 15 schools in New South Wales, Australia, a proportion of 863 close contacts were either screened by RTPCR or for antibodies. Two children may have contracted Covid-19 from the initial cases. No other teacher or staff member was infected. No evidence of children infecting teachers was found.
The authors concluded, “It is notable that half of the initial cases that occurred in schools were in staff. This is consistent with the higher rate of Covid-19 seen in adults than in children. This reinforces the need for both adults and children to ensure they do not attend school when ill and if they become ill to promptly isolate themselves and seek medical attention. It is also important for all adults, including teachers, to follow recommended social distancing practices while at school and in the community.”
Children less likely to be index case
A literature review of 31 household transmission clusters from China, Singapore, South Korea, Japan, and Iran showed that only 9.7 per cent started from a child index case. Data from Guangzhou found this rate to be 5 per cent. On the other hand, the majority of children infected by Covid-19 have been part of a family cluster outbreak by adults, who got infected outside the household.
Take home points
While the infection rates in children are low, and 55 per cent are mild or asymptomatic, they can get critically sick too, especially teens, or bring the virus back home.
Teachers should protect their students by wearing masks, and perhaps help all children to make DIY masks, which is more sustainable in the long run.
Frequent handwashing with soap and water is key. Where sinks are too far away, a simple bucket of clean water with a ladle and another empty one that kids can wash their hands and pour water into, may be a cheap option. The bucket of dirty soapy water can be recycled to wash drains. Both buckets can be sanitised with diluted bleach at the end of the day.
Schools with dormitories should be particularly vigilant when their students, teachers, or support staff are not well. These are potential super-spreader hotspots. Early diagnosis and admission can prevent deterioration and death.
So far no children have died in Malaysia from Covid-19. Perhaps this is one of the very few zeros educationists and parents will be very happy to continue to see on our favourite DG MoH daily Covid-19 reports. Syabas.
Dr Tan Poh Tin is a public health trained paediatrician.