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Comparison of RT-PCR Cycle Threshold Values from Respiratory Specimens in Symptomatic and Asymptomatic Children with
John Strutner1, Nanda Ramchandar2, Shruti Dubey3
1Department of Pediatrics, University of California San Diego, USA.
Insights
Symptomatic children infected with SARS-CoV-2 have a significantly lower PCR cycle threshold (Ct) value, indicating a higher viral load. This finding was most pronounced in children under 5 years old, suggesting increased transmission potential.
Area of Science:
- Pediatric Infectious Diseases
- Virology
- Public Health
Background:
- Understanding SARS-CoV-2 viral kinetics is crucial for managing transmission, treatment, and isolation protocols.
- The transmission potential of asymptomatic infected children requires further investigation.
- Viral load in asymptomatic pediatric cases of SARS-CoV-2 remains an area of interest.
Purpose of the Study:
- To compare the PCR cycle threshold (Ct) values between symptomatic and asymptomatic children infected with SARS-CoV-2.
- To investigate the relationship between viral load and age in pediatric SARS-CoV-2 infections.
Main Methods:
- Retrospective cross-sectional study design.
- Analysis of respiratory samples from children testing positive for SARS-CoV-2 via RT-PCR.
- Data collected over a 4-month period at a tertiary care children's hospital.
Main Results:
- A total of 728 children positive for SARS-CoV-2 were analyzed.
- Symptomatic children (71.2%) had a significantly lower mean Ct value (19.9) compared to asymptomatic children (23.5).
- The lowest mean PCR Ct values were observed in children under 5 years of age.
Conclusions:
- Symptomatic children and younger children (<5 years) infected with SARS-CoV-2 may exhibit higher nasopharyngeal viral loads.
- Lower Ct values in symptomatic and younger children suggest potentially greater transmission.
- Further research is warranted to fully assess transmission risks from asymptomatic pediatric SARS-CoV-2 cases.
Background:
Understanding viral kinetics of SARS-CoV-2 is important to assess risk of transmission, manage treatment, and determine the need for isolation and protective equipment. The impact of viral load in asymptomatic infected children is important to understand transmission potential. We sought to determine whether children deemed to be asymptomatic had a difference in the PCR cycle threshold (Ct) value of respiratory samples from symptomatic children with SARS-CoV-2 infection.
Methods:
This was a retrospective cross-sectional study to compare PCR Ct values of children who tested positive for SARS-CoV-2 by respiratory samples collected over a 4-month period at a large tertiary care children's hospital.
Results:
We analyzed 728 children who tested positive for SARS-CoV-2 by RT-PCR from a respiratory sample over a 4-month period and for whom data was available in the electronic medical record. Overall, 71.2% of infected children were symptomatic. The mean Ct value for symptomatic patients (Ct mean 19.9, SD 6.3) was significantly lower than asymptomatic patients (Ct mean 23.5, SD 6.5) (P value < 0.001, CI 95th 2.6 - 4.6). The mean PCR Ct value was lowest in children less than 5 years of age.
Conclusions:
In this retrospective review of children who tested positive by RT-PCR for SARS CoV-2, the mean Ct was significantly lower in symptomatic children and was lowest in children under 5 years of age, indicating that symptomatic children and younger children infected with SARS-CoV-2 may have a higher viral load in the nasopharynx compared to asymptomatic children. Further studies are needed to assess the transmission potential from asymptomatic children.
