The reopening of schools around the world coincided with the surge in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to the emergence of the Delta variant of concern. However, little information regarding the early symptoms in children infected with the Delta variant existed.
The lack of information complicated the development of school policy regarding which symptoms possessed by a newly symptomatic child should lead to exclusion of the child from school or childcare facilities until they test negative for SARS-CoV-2. Some policies state that children with a single symptom can attend school and do not require testing for SARS-CoV-2.
Although a recent study from the UK described the most common symptoms observed over the first week of illness in children infected with the Delta variant, it did not provide any information on the prevalence or predictive value of isolated symptoms or the time course of the symptoms.
A new study published in the pre-print server medRxiv* compared rates of coronavirus disease 2019 (COVID-19) infection in children who reported no symptoms, one isolated symptom, or two or more symptoms in a high prevalence area during the circulation of the Delta variant. The study also evaluated the predictive value of each isolated symptom along with the impact of vaccination status, age, and contacts on contracting COVID-19.
The study included patients who were 0 to 18 years of age and presented to one of six ambulatory testing sites in Georgia between 4th July and 15th October 2021. The participants had to take part in the following procedures: nasopharyngeal PCR testing for SARS-CoV-2 infection, review of the symptoms that were present at the time of testing along with the overall symptom duration, and collection of additional samples for future research.
The participants and their families were asked for the presence of any of the common symptoms associated with SARS-CoV-2 infection such as fever, cough, chills, headache, myalgia, nausea, diarrhea, vomiting, or any other symptoms. Following this the participants were categorized as asymptomatic, having one symptom or having two or more symptoms. Also, the vaccination status of the participants was ascertained.
The results indicated that out of the 602 participants who had taken part in the study, 155 were asymptomatic, 82 reported only one symptom, and 365 reported two or more symptoms at the time of testing. The most common symptom for those with only one symptom was congestion/rhinorrhea followed by cough, fever, sore throat, and headache. However, the duration of symptoms for the group with one symptom and the group with two or more symptoms were equal.
The percentage of participants who had a known and/or suspected close contact with COVID-19 was found to be 48.7 percent. The proportion of exposure to a known or suspected contact with COVID-19 was higher in the case of the group with one or no symptoms as compared to the group with two or more symptoms.
The children with one symptom were six times more likely to test positive for COVID-19 while the children with two or more symptoms were 5.25 times more likely to test positive for COVID-19 as compared to the asymptomatic children. The study also reported that when the known or suspected exposure status was kept constant, children with one and two or more symptoms had a higher chance of testing positive for COVID-19 as compared to children with no symptoms.
Furthermore, if the cohort was broken down into the elementary, middle, and high school-aged children, similar findings could be observed. Elementary, middle, and high school-aged children with one symptom were 4.06, 19.43, and 10 times more likely to test positive for COVID-19 as compared to those with no symptom. Elementary, middle, and high school-aged children with two or more symptoms were 1.99, 21.25, and 26.96 times more likely to test positive for COVID-19 as compared to the ones with no symptoms.
The results also indicated that the likelihood of contracting COVID-19 depended on the presence of symptoms and not on the number of symptoms that were present. Among the isolated symptoms, the ones with the highest sensitivity were fever, congestion/rhinorrhea, cough, and sore throat.
The current study, therefore, demonstrates that children with isolated symptoms were as likely to contract COVID-19 as those with multiple symptoms. Certain isolated symptoms have high predictive values indicating that the presence of these symptoms could suggest school exclusion and COVID-19 testing. However, further research needs to be carried out to understand the extent to which the findings of this study can be generalized.
The study had certain limitations. First, the study was relatively small with no information regarding the severity of each symptom and the reason for not testing asymptomatic individuals. Second, the study did not include data on Ct values or viral loads in the case of the positive samples. Third, sequencing was not done to ensure that the Delta variant was responsible for causing infections in children. Fourth, the exposure of the population to known or suspected cases with COVID-19 was high. Finally, the study included very few vaccinated children to be able to conclude symptom presentation in this subgroup.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.