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Association Between Real-time Polymerase Chain Reaction Cycle Threshold Value and Clinical Severity in Neonates and
Do Thi Thuy Nga1, Phung Thi Bich Thuy2, Akira Ainai3
1From the Division of General Internal Medicine, The Center for Tropical Diseases, Vietnam National Children's Hospital, Hanoi, Vietnam.
Background:
Polymerase chain reaction (PCR) is highly sensitive and is thus the standard method for diagnosing pertussis. Real-time PCR is widely used because of its accuracy and the simplicity of the simultaneous cycle threshold (Ct) value, which represents the copy numbers of the target gene. Little is known of the association of Ct value with pertussis severity in neonates and infants.
Methods:
This study determined Ct values in neonates and infants diagnosed with pertussis by real-time PCR using nasopharyngeal samples at Vietnam National Children's Hospital in Hanoi in 2017 and 2019. The association of disease severity and clinical parameters were analyzed using univariate and multivariate analyses.
Results:
We evaluated 108 patients with pertussis [median age: 63 days, interquartile range (IQR): 41-92 days]. Only 6/108 (6%) received at least 1 dose of a pertussis-containing vaccine. Among them, 24 (22.2%) had severe disease requiring care in a pediatric intensive care unit, 16 (13.8%) required mechanical ventilation, and 3 (2.6%) died. The median Ct value was lower in patients with severe disease (19.0, IQR: 16.5-22.0, n = 24) than in those without severe disease (25.5, IQR: 20.0-30.0, n = 84) (P = 0.002). Logistic regression analyses demonstrated that PCR Ct value [odds ratio (OR): 1.783, 95% confidence interval (CI): 1.013-3.138, P = 0.045], age (OR: 3.118, 95% CI: 1.643-5.920, P = 0.001), and white blood cell counts (OR: 0.446, 95% CI: 0.261-0.763, P = 0.003) remained significantly associated with severe disease.
Conclusions:
Real-time PCR Ct values for pertussis might be useful as a predictor of severe disease in neonates and infants.
Insights
Real-time PCR cycle threshold (Ct) values can predict pertussis severity in infants. Lower Ct values indicate a higher likelihood of severe disease, aiding in early diagnosis and management of pertussis in this vulnerable population.
Area of Science:
- Pediatric Infectious Diseases
- Molecular Diagnostics
- Public Health Microbiology
Background:
- Pertussis (whooping cough) diagnosis relies on highly sensitive Polymerase Chain Reaction (PCR).
- Real-time PCR provides accurate quantification of target genes via cycle threshold (Ct) values.
- The association between Ct values and pertussis severity in neonates and infants is not well understood.
Purpose of the Study:
- To investigate the relationship between real-time PCR Ct values and the severity of pertussis in infants.
- To identify potential predictors of severe pertussis disease in neonates and young children.
Main Methods:
- Real-time PCR Ct values were determined from nasopharyngeal samples of 108 infants diagnosed with pertussis.
- Clinical data, including disease severity and need for intensive care, were collected.
- Univariate and multivariate logistic regression analyses were used to assess associations.
Main Results:
- Severe pertussis cases (requiring ICU care, ventilation, or resulting in death) had significantly lower median Ct values (19.0) compared to non-severe cases (25.5).
- PCR Ct value, younger age, and white blood cell counts were significant predictors of severe pertussis.
- Only 6% of the evaluated infants had received any pertussis vaccination.
Conclusions:
- Real-time PCR Ct values may serve as a valuable tool for predicting pertussis severity in neonates and infants.
- Lower Ct values are associated with increased risk of severe outcomes in young children with pertussis.
