RSV associated hospitalizations in children in Karachi, Pakistan: Implications for vaccine prevention strategies

Abstract

Major progress is being made in vaccines against Respiratory Syncytial Virus (RSV), with multiple vaccine candidates currently in the clinical phase of development. Making an investment case for public sector financing of RSV vaccine will require estimation of burden, cost-effectiveness and impact. The aim of this study is to determine the proportion, age distribution and clinical spectrum of RSV associated hospitalizations in children in Karachi, Pakistan. A three years prospective study was conducted at the Aga Khan University hospital in Karachi, a city of 20 million in south Pakistan, from August 2009 to June 2012. Children less than five years old admitted with acute respiratory infections (ARI) were enrolled. Throat swabs were collected and tested for RSV using real-time PCR. Multivariable log binomial regression analysis was performed to identify the associated factors of RSV infection. Out of 1150 children enrolled, RSV was detected among 223 (19%). Highest rate of RSV detection was in young infants less than 3 months of age (48/168, 29%), which accounted for 22% of all RSV detected. Most common diagnosis in RSV positive infants (<12 months of age) was bronchiolitis followed by pneumonia, while in older children between the ages of one and five years of age, pneumonia and asthma were the most common diagnosis. Although identified year-round, RSV was most prevalent from August to October with peak in September, coinciding with the rainy season. This study identified RSV to be independently associated with younger age (p=0.036), rainy season (p<0.001), post-tussive emesis (p=0.008), intubation (p=0.003) and discharge diagnosis of bronchiolitis (p=0.004). Vaccines against RSV that target this age group are likely to yield remarkable benefit.

Human metapneumovirus in hospitalized children less than 5 years of age in Pakistan

“…Karachi is the capital of Sindh province in Pakistan, and is one of the most populous cities in the world with a population of approximately 20 million. The detail setting and other methods are reported elsewhere …”

The Impact of RSV-Associated Respiratory Disease on Children in Asia

“…Jan 2008-Dec 2008 51 16 y 51 25.0 51 Early spring to winter, with a peak from Jan to Apr 51 Hong Kong Jan 2004-Dec 2004 52 3 y 52 11.6 52 No winter seasonality 3 57 All ages 57 8.9 57 Detected most month of the year with a peak from Jun to Oct 57 Aug 2009-Jun 2012 63 < 5 y 63 19 63 Peak in Sep coinciding with the rainy season 63 Abbreviations: NA, not available; RSV, respiratory syncytial virus.…”

Etiology of acute viral respiratory infections common in Pakistan: A review

“…The most noteworthy rate of RSV identification was in infants under 3 months of age (48/168, 29%), which represented 22% of all RSV distinguished. Most normal determination in RSV positive babies (<12 months of age) was bronchiolitis trailed by pneumonia whereas in other study, 7% (84 out of 1150) of the cases were identified with the presence of HMPV, 67% (56 out of 84) of which were children under 1 year of age, and these cases were characterized by bronchiolitis trailed by pneumonia …”

“…RSV appeared to be more incident from August to October and highest in September. Susceptibility increased in rainy seasons . HMPV was detected in 7% of the cases in the above scenario, most of which were children under 1 year of age …”

“…RSV association with kids between the ages of one and 5 years old suffering from pneumonia and asthma was the most widely recognized finding of a 3‐year study conducted in Karachi from August 2009 to June 2012. In older children between the ages of one and 5 years old, pneumonia and asthma were the most widely recognized findings . In another study conducted by the group, the cases were characterized by pneumonia followed by bronchiolitis …”