Parainfluenza Virus Infection in an Australian Community-based Birth Cohort

Respiratory Viral Testing Rate Patterns in Young Children Attending Tertiary Care Across Western Australia: A Population-Based Birth Cohort Study

BACKGROUND

An understanding of viral testing rates is crucial to accurately estimate the pathogen-specific hospitalisation burden. We aimed to estimate the patterns of testing for respiratory syncytial virus (RSV), influenza virus, parainfluenza virus (PIV) and human metapneumovirus (hMPV) by geographical location, age and time in children <5 years old in Western Australia.

METHODS

We conducted a population-based cohort study of children born between 1 January 2010 and 31 December 2021, utilising linked administrative data incorporating birth and death records, hospitalisations and respiratory viral surveillance testing records from state-wide public pathology data. We examined within-hospital testing rates using survival analysis techniques and identified independent predictors of testing using binary logistic regression.

RESULTS

Our dataset included 46,553 laboratory tests for RSV, influenza, PIV, or hMPV from 355,021 children (52.5% male). Testing rates declined in the metropolitan region over the study period (RSV testing in infants: from 242.11/1000 child-years in 2012 to 155.47/1000 child-years in 2018) and increased thereafter. Conversely, rates increased in non-metropolitan areas (e.g., RSV in Goldfields: from 364.92 in 2012 to 504.37/1000 child-years in 2021). The strongest predictors of testing were age <12 months (adjusted odds ratio [aOR] = 2.25, 95% CI 2.20-2.31), preterm birth (<32 weeks: aOR = 2.90, 95% CI 2.76-3.05) and remote residence (aOR = 0.77, 95% CI 0.73-0.81).

CONCLUSION

These current testing rates highlight the potential underestimation of respiratory virus hospitalisations by routine surveillance and the need for estimation of the true burden of respiratory virus admissions.

Human bocavirus-1 infections in Australian children aged < 2 years: a birth cohort study

To determine human bocavirus-1 (HBoV1) infection characteristics in young Australian children. Data were from the Observational Research in Childhood Infectious Diseases (ORChID) study, a Brisbane, Australia-based birth cohort of healthy, term, newborns followed prospectively for 2 years. Parents recorded daily symptoms, maintained an illness-burden diary, and collected weekly nasal swabs, which were tested for 17 respiratory viruses, including HBoV1, by real-time polymerase chain reaction (PCR) assays. Main outcomes measured were infection incidence, risk factors, symptoms, and healthcare use. One hundred fifty-eight children in the ORChID cohort provided 11,126 weekly swabs, of which 157 swabs were HBoV1 positive involving 107 incident episodes. Co-detections were observed in 65/157 (41.4%) HBoV1-positive swabs (or 41/107 [38.3%] infection episodes), principally with rhinovirus. Shedding duration was 1 week in 64.5% of episodes. The incidence of HBoV1 infections in the first 2 years of life was 0.58 episodes per child-year (95% confidence interval [CI] 0.47-0.71), including 0.38 episodes per child-year (95% CI 0.30-0.49) associated with respiratory symptoms. Recurrent episodes occurred in 18/87 (20.7%) children following their primary infection. In the first 2 years of life, incidence of HBoV1 episodes increased with age, during winter and with childcare attendance. Overall, 64.2% of HBoV1 episodes were symptomatic, with 26.4% having healthcare contact. Viral load estimates were higher when children were symptomatic than when asymptomatic (mean difference = 3.4; 95% CI 1.0-5.7 PCR cycle threshold units). After age 6 months, HBoV1 is detected frequently in the first 2 years of life, especially during winter. Symptoms are usually mild and associated with higher viral loads.

Epidemiological Characteristics of Parainfluenza Virus Type 3 and the Effects of Meteorological Factors in Hospitalized Children With Lower Respiratory Tract Infection

Objective

To investigate the relationship between meteorological factors and Human parainfluenza virus type 3 (HPIV-3) infection among hospitalized children.

Methods

All hospitalized children with acute lower respiratory tract infections were tested for viral pathogens and enrolled, at the second affiliated hospital of Wenzhou medical university, between 2008 and 2017. Meteorological data were directly obtained from Wenzhou Meteorology Bureau's nine weather stations and expressed as the mean exposure for each 10-day segment (average daily temperatures, average daily relative humidity, rainfall, rainfall days, and wind speed). The correlation between meteorological factors and the incidence of HPIV-3 was analyzed, with an autoregressive integrated moving average model (ARIMA), generalized additive model (GAM), and least absolute shrinkage and selection operator (LASSO).

Results

A total of 89,898 respiratory specimens were tested with rapid antigen tests, and HPIV-3 was detected in 3,619 children. HPIV-3 was detected year-round, but peak activities occurred most frequently from March to August. The GAM and LASSO-based model had revealed that HPIV-3 activity correlated positively with temperature and rainfall day, but negatively with wind speed. The ARIMA (1,0,0)(0,1,1) model well-matched the observed data, with a steady R2 reaching 0.708 (Ljung-Box Q = 21.178, P = 0.172).

Conclusion

Our study suggests that temperature, rainfall days, and wind speed have significant impacts on the activity of HPIV-3. GAM, ARIMA, and LASSO-based models can well predict the seasonality of HPIV-3 infection among hospitalized children. Further understanding of its mechanism would help facilitate the monitoring and early warning of HPIV-3 infection.

Respiratory virus detection during the COVID-19 pandemic in Queensland, Australia

OBJECTIVE

To determine if non-pharmaceutical interventions (NPIs) impacted on respiratory virus detections in Queensland, Australia, during the COVID-19 pandemic year of 2020.

METHODS

We analysed weekly counts of influenza, human metapneumovirus, parainfluenza, respiratory syncytial virus, rhinovirus, and adenovirus available from a Queensland laboratory network for the year 2020. These were compared with averaged counts from 2015 to 2019.

RESULTS

Overall, 686,199 tests were performed. The timing of NPI implementation was associated with a sharp and sustained decline in influenza, where during the typical annual influenza season (weeks 23-40) no cases were detected from 163,296 tests compared with an average of 26.1% (11,844/45,396) of tests positive in 2015-2019. Similar results were observed for human metapneumovirus and parainfluenza. Respiratory syncytial virus detections also declined but increased in weeks 48-52 (5.6%; 562/10,078) to exceed the 2015-2019 average (2.9%; 150/5,018). Rhinovirus detections increased after schools reopened, peaking in weeks 23-27 (57.4%; 36,228/63,115), exceeding the 2017-2019 detections during that period (21.9%; 8,365/38,072).

CONCLUSIONS

NPIs implemented to control COVID-19 were associated with altered frequency and proportions of respiratory virus detections. Implications for public health: NPIs derived from influenza pandemic plans were associated with profound decreases in influenza detections during 2020.

Effects of climatic factors on human parainfluenza 1, 2, and 3 infections in Cheonan, Republic of Korea

Studying relationships between meteorological conditions and respiratory virus infections may help interpret the causality of disease outbreaks and provide a better understanding of the seasonal distribution of viruses. Therefore, in this study, we analyzed the correlations between meteorological data and the trends of infection by human parainfluenza virus-1 (HPIV-1; also known as human respirovirus 1), human parainfluenza virus-2 (human orthorubulavirus 2), and human parainfluenza virus-3 (human respirovirus 3) using 9010 viral samples collected at Dankook University Hospital from January 1, 2012, to December 31, 2018. Infection frequency data were used to detect the seasonal patterns of HPIV-1, HPIV-2, and HPIV-3 infections, and these patterns were compared with local weather data over the same period. We performed descriptive statistical analysis, frequency analysis, t test, and binomial logistic regression analysis to examine the relationships of weather and particulate matter conditions with the incidence of HPIV-1, HPIV-2, and HPIV-3 infections. The highest average infection rate with one of these three viruses (88.17%) was found in children aged 1-9 years. Specifically, the infection rate of HPIV-1 was 91.9% in children aged 1-9 years, whereas that of HPIV-2 and HPIV-3 was 86.3%. HPIV infection exhibited a meaningful relationship with climatic factors, such as temperature, wind-chill temperature, and atmospheric pressure. Our results suggest that climate changes might affect the rate of infection by HPIV. These findings may help in predicting the effectiveness of preventive strategies of HPIV infection.