A new preprint study has shown that in areas with high community transmission of delta variant, children with isolated symptoms associated with Covid-19 were as likely to have the infection as those who reported more than one symptom.

Patients aged ≤ 18 years presented to one of six ambulatory testing sites in Georgia between 4th July and 15th October 2021 during the peak of the SARS-CoV-2 delta variant, were enrolled in the study. They were asked about the common presenting symptoms of Covid-19 and the duration of symptoms, at the time of testing for SARS-CoV-2 via nasopharyngeal swab RT PCR and their vaccination status. Based on the symptoms present, the 602 participants were grouped into three: 155 with no symptoms (25.2% previously vaccinated), 82 with one symptom (13.4% previously vaccinated) and 365 with ≥2 symptoms (9.0% previously vaccinated). The sensitivity, specificity, and positive/negative predictive values (PPV/NPV) for isolated symptoms were calculated.

The symptoms evaluated in the study included fever (either subjective or > 100.4^oF), chills, congestion/rhinorrhea, cough, headache, sore throat, fatigue, arthralgias, myalgias, photophobia, vomiting, nausea, diarrhea, abdominal pain, loss of sense of taste or smell, shortness of breath, or any other. Overall, almost half of the participants had a known and/or suspected close contact with Covid-19. Children with one symptom were exposed more to Covid-19 (57.3%) compared to those who reported ≥2 symptoms (44.4%). However, the exposure was comparable in children with one symptom and asymptomatic (57.3% vs 54.2%).

Results showed that compared to asymptomatic children, those who had one symptom had six times higher probability of testing positive for Covid-19; while those who ≥2 symptoms were 5.25 more likely to test positive for Covid-19.

Among patients reporting just one symptom, congestion/rhinorrhea (26.8%) was the most common symptom followed by cough (23.2%), fever (17.1%), sore throat (13.4%), and headache (7.3%).

Isolated symptoms with highest sensitivity and PPV were isolated fever (33%/57%), cough (25%/32%) and sore throat (21%/45%). Headache had low sensitivity (8%) but higher PPV (33%), while symptoms of congestion and rhinorrhea had low sensitivity and PPV (8% and 9%) suggesting that children who had congestion/rhinorrhea only (OR=2.47) had similar odds of testing positive as children who did not have congestion/rhinorrhea.

Age-wise analysis of the participants was also done for which they were categorized into three age groups: ≤10 years (elementary school), 11-13 years (middle school) and 14-18 years (high school). Participants in all the three age groups with only one symptom or those with ≥2 symptoms were more likely to test positive compared to children who had no symptoms at presentation.

 “Elementary, middle, and high school-aged children with only one symptom were 4.06, 19.43 and 10.00 times as likely, respectively, to test positive for COVID-19 as children with no symptoms.

Elementary, middle, and high school-aged children with ≥2 symptoms were 1.99, 21.25 and 26.96 times as likely, respectively, to test positive for COVID-19 than children with no symptoms, though this difference was not significant in elementary-aged children.”

However, the chance of testing positive was comparable among elementary, middle, and high school-aged children with ≥2 symptoms and those with only one symptom, again implying that it was the presence of just one symptom, rather than multiple symptoms, which increased the odds of testing positive.

In this study, isolated symptoms such as fever, headache, sore throat, cough had the highest predictive value, while congestion/rhinorrhea, though common, had lower predictive value. Fever had the highest sensitivity and PPV among isolated symptoms examined. Children who had one symptom and those who had two or more symptoms had similar risks of testing positive suggesting that “the likelihood of having COVID-19 was not dependent on the number of symptoms, but rather that a symptom was present.” Also, “These findings remained consistent with exclusion of children with fever or vaccination and after controlling for known/suspected close contacts in sensitivity analyses, and were true for all three school age groups.”

Since schools have reopened across the country, this study has public health implications. Children should be considered for Covid-19 testing even if they have just one presenting symptom and should be advised to not attend schools.

Reference

1. Westbrook AL, et al. Predictive value of isolated symptoms for diagnosis of SARS-CoV-2 infection in children tested during peak circulation of the delta variant. medRxiv. Posted December 17, 2021. doi: https://doi.org/10.1101/2021.12.17.21267993.