Virtually all deaths from RSV occur in developing countries, and long-term airway morbidity should be studied in those parts of the world.
Louis J. Bont, MD
Respiratory syncytial virus (RSV), a virus that infects the respiratory tract, does not cause current asthma or poor lung function by 6 years of age, according to a new study.
There are hundreds of clinical publications focusing on the relationship between RSV and asthma, noted study author Louis J. Bont, MD, Pediatric Infectious Disease Specialist at Wilhelmina Children’s Hospital, University Medical Center Utrecht, in the Netherlands.
That may be because RSV infection is one of the most common cause of disease during infancy, Bont said.
“We provided the first conclusive evidence that RSV does not cause asthma symptoms and does not increase the risk of asthma,” Bont said.
Authors previously conducted the MAKI trial, an exploration of the relationship between prevention of RSV infection during infancy and reduced frequency of subsequent asthma. These current study results are a follow-up, analyzing the effects of RSV prevention during infancy on asthma and lung function at age 6. Subjects included 429 infants born at 32 to 35 weeks between 2008 and 2010, who randomly received palivizumab for RSV or placebo during RSV season (mid-fall to early spring).
The six-year follow-up included 92% of the original participants. Parent-reported current asthma was reported in 28 (14.1%) of 199 children in the RSV prevention group and 47 (24%) of 196 children in the placebo group (ARR 9.9%; 95% CI; 2.2 - 17.6). The difference in current asthma was the result of infrequent wheeze (1 to 3 episodes within the past year; 12 [6.0%] of 199 vs. 26 [13.4%] of 194; ARR 7.4%; 95% CI; 1.5 - 13.2).
Forced expiratory volume (FEV) 0.5 percentage predicted values were similar between RSV prevention group (89.1% [SD 10.6]) and placebo group (90.1% [11.1]), with a mean difference of 1.0 (95% CI; -1.3 - 3.3). The number of children with current doctor-diagnosed asthma was similar between the RSV group (19 [10.3%] of 185) and the placebo group (18 [9.9%] of 182); ARR -0.4; 95% CI; -6.5 - 5.8).
“This is good news for parents of patients with RSV infection,” said Bont. “We can tell them that the infection has not increase their child’s risk for asthma.”
Bont added that virtually all deaths from RSV occur in developing countries and that long-term airway morbidity should be studied in those parts of the world.
“The development of RSV vaccines is also rapidly advancing,” Bont said. “I would like to see asthma follow-up studies in these vaccines trials. Based on the results of our study, it becomes clear that objective outcomes with lung function are critically important.”
The study, "Respiratory syncytial virus prevention and asthma in healthy preterm infants: a randomised controlled trial," was published online in The Lancet Respiratory Medicine.
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