COVID-19 and Asthma
In December 2019, a cluster of pneumonia cases caused by an unknown pathogen was noticed in Wuhan, China. Deep sequencing analysis of samples from the lower respiratory tract revealed a novel coronavirus which was named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 mainly affects adults. Children and adolescents are less likely to have severe COVID-19. The effects on asthma in children are not clear.
A summary of 44,672 confirmed COVID-19 cases reported in February 2020 by the Chinese Center for Disease Control and Prevention, revealed that 90% of these cases were 30 years or older and only 1% were 9 years or younger. The case-fatality rate was 2.3% overall: 8% in patients aged 70-79 years; and 14.8% in patients aged ≥80 years; but no deaths in those aged 9 years or younger.
During the pandemic of COVID-19, children with asthma experienced fewer upper respiratory tract infections, emergency visits, asthma attacks, and hospitalisations due to asthma, probably due to public health interventions leading to reduced exposure to asthma triggers. Clinical manifestations of COVID-19 among children with asthma have rarely been reported. It has been unclear whether SARS-CoV-2 is associated with exacerbations of asthma.
Global Asthma Network (GAN) survey on COVID-19 among children with asthma
To improve the global understanding of COVID-19 and childhood asthma, the GAN Steering Group conducted a survey among its worldwide network, on clinical manifestations and outcomes of infection with SARS-CoV-2 among children with asthma. A standardised questionnaire was developed and sent to 133 centres from 59 countries in November 2020. Data collection closed on 28th April 2021. The sampling frame included asthmatic children who had been tested in contact examination, in a clinical practice or in a hospital of each participating centre. All asthmatic children who tested positive for SARS-CoV-2 were included, regardless of symptoms.
Fourteen GAN centres from 10 countries (Argentina, Belarus, Brazil, Greece, Guatemala, Iran, Kyrgyzstan, the Kingdom of Saudi Arabia, Spain, and Sudan) provided data on 169 asthmatic children infected with SARS-CoV-2 confirmed by reverse transcription polymerase chain reaction tests.
Findings of the GAN survey
Of the 169 participant children, 111 (65.7%) were symptomatic and 76 (45.0%) had a body temperature >37.5 °C. Common symptoms included cough, headache, rhinorrhoea, fatigue, and smell reduction. Thirty-eight (22.5%) patients had exacerbations of asthma associated with SARS-CoV-2 infection; 53 (31.4%) had a change of asthma medicines. COVID-19 was asymptomatic in 58 (34.3%), mild in 93 (55.0%), moderate in 14 (8.3%) and severe/critical in 4 (2.4%). Twenty-one (12.4%) patients had been hospitalised for a median of seven days.
Adolescents aged 14 years or older were significantly more likely to be symptomatic than children aged under 10 years. Patients from high-income countries were significantly less likely to be symptomatic than patients from other countries. Use of ICS and other asthma medications were not significantly associated with being symptomatic. Patients from high-income countries were significantly less likely to have moderate or more severe COVID-19 than patients from other countries. Use of ICS and other asthma medications were not significantly associated with moderate or more severe COVID-19.
Those who had moderate or more severe COVID-19 were significantly more likely to have had an exacerbation of asthma as compared to those who were asymptomatic or had mild COVID-19. Use of ICS and other asthma medicines were not associated with asthma exacerbations.
Those who used inhaled bronchodilators were significantly more likely to have a change of asthma medications compared to those who did not. Those who had moderate or more severe COVID-19 were significantly more likely to be hospitalised as compared to those who were asymptomatic or mild COVID-19. Use of ICS and other asthma medications were not significantly associated with hospitalisation.
Other COVID-19 studies among children with asthma
Various studies have reported that the proportions of COVID-19 cases who were asymptomatic among children were 13% - 28%; moderate disease ranged from 19% to 64.9%; and 2% to 3% had severe/critical illness. The GAN COVID-19 survey revealed that children with asthma did not have high morbidity from COVID-19, although a small proportion had severe/critical disease.
A substantial proportion of asthmatic children had exacerbations of asthma and a considerable proportion had a change of asthma medicines associated with infection with SARS-CoV-2. However, the severity of COVID-19 was significantly associated with exacerbations of asthma and a change of asthma medicines. Whether symptoms leading to a change of asthma medicines were caused by COVID-19 or due to exacerbations of asthma was less clear.
The GAN survey revealed that the use of an inhaled bronchodilator was associated with a change of asthma medications, likely indicating that their asthma was not appropriately controlled. However, the use of ICS was not associated with severity of COVID-19, exacerbations of asthma, a change of asthma medicines and hospitalisation in children infected with SARS-CoV-2. This finding clearly supports the recommendation of continuing the use of ICS among patients with asthma.