Modeling the impact of COVID-19 nonpharmaceutical interventions on respiratory syncytial virus transmission in South Africa

Inhibition, transition, and surge: dynamic evolution of pediatric respiratory pathogen trends amid COVID-19 pandemic policy adjustments

Background

The implementation of a zero-COVID policy for 3 years in China during the COVID-19 pandemic significantly impacted a broad spectrum of acute respiratory tract infections (ARTIs). The epidemiological characteristics of ARTI pathogens in children following the cessation of the zero-COVID policy remain unclear.

Methods

Etiologically diagnostic data from 82,708 children with ARTIs at the Children's Hospital of Soochow University during 2016-2023 were analyzed for 8 pathogens (human respiratory syncytial virus [HRSV], influenza A [FluA], FluB, human parainfluenza virus [HPIV], adenovirus [ADV], human rhinovirus [HRV], bocavirus [BoV], and mycoplasma pneumoniae [MP]). The changes in respiratory infections in Suzhou, China during the first year (2020, Phase I) and the second and third years of the pandemic (2021-2022, Phase II) and the first year after the end of zero-COVID policy (2023, Phase III) versus that in the pre-pandemic years (2016-2019) were compared.

Results

When compared with the average pre-pandemic levels, the pathogen-positive rate decreased by 19.27% in Phase I (OR: 0.70; 95% CI: 0.67-0.74), increased by 32.87% in Phase II (OR: 1.78; 95% CI: 1.72-1.84), and increased by 79.16% in Phase III (OR: 4.58; 95% CI: 4.37-4.79). In Phase I, the positive rates of HRSV, FluA, ADV, and MP decreased by 26.72, 58.97, 72.85, and 67.87%, respectively, and the positive rates of FluB, HPIV, HRV, and BoV increased by 86.84, 25, 32.37, and 16.94%, respectively. In Phase III, the positive rates of HRSV, FluA, FluB, HPIV, ADV, and HRV increased by 39.74, 1046.15, 118.42, 116.57, 131.13, and 146.40%, respectively, while the positive rate of BoV decreased by 56.12%. MP was inhibited during the epidemic, and MP showed a delayed outbreak after the ending of the zero-COVID policy. Compared with the average pre-pandemic levels, the MP-positive rate in Phase III increased by 116.7% (OR: 2.86; 95% CI: 2.74-2.99), with the highest increase in 0-1-year-old children.

Conclusion

The strict and large-scale implementation of the zero-COVID policy in the early stages of the COVID-19 pandemic was the main driving factor for the sharp reduction in the rate of children's respiratory pathogenic infections. The termination of this policy can cause a resurgence or escalation of pathogenic infections.

Risk Factors for Severe COVID-19 Among Children and Adolescents Enrolled in Acute Respiratory Infection Sentinel Surveillance in South Africa, 2020-2022

BACKGROUND

Identifying children at risk for severe COVID-19 disease from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may guide future mitigation interventions. Using sentinel surveillance data, we aimed to identify risk factors for SARS-CoV-2-associated hospitalisation among patients aged ≤ 18 years with respiratory illness.

METHODS

From April 2020 to March 2022, patients meeting study case definitions were enrolled at four outpatient influenza-like illness (ILI) and five inpatient severe respiratory infection (SRI) surveillance sites and tested for SARS-CoV-2 infection using polymerase chain reaction (PCR). Each ILI clinic shared a catchment area with its corresponding SRI hospital. Potential risk factors for SARS-CoV-2-associated hospitalisation were analysed using multivariable logistic regression by comparing inpatient versus outpatient SARS-CoV-2 cases.

RESULTS

Of 4688 participants aged ≤ 18 years, 4556 (97%) with complete PCR and HIV data were included in the analysis. Among patients with ILI and SRI, 92/1145 (8%) and 154/3411 (5%) tested SARS-CoV-2 positive, respectively. Compared to outpatients, hospitalised SARS-CoV-2 cases were associated with age < 6 months ([adjusted odds ratio (aOR) 8.0, 95% confidence interval (CI) 2.7-24.0] versus 1-4 years); underlying medical condition other than HIV [aOR 5.8, 95% CI 2.3-14.6]; laboratory-confirmed Omicron BA.1/BA.2 or Delta variant ([aOR 4.9, 95% CI 1.7-14.2] or [aOR 2.8, 95% CI 1.1-7.3] compared to ancestral SARS-CoV-2); and respiratory syncytial virus coinfection [aOR 6.2, 95% CI 1.0-38.5].

CONCLUSION

Aligning with previous research, we identified age < 6 months or having an underlying condition as risk factors for SARS-CoV-2-associated SRI hospitalisation and demonstrated the potential of sentinel surveillance to monitor COVID-19 in children.