Diagnosis, admission, discharge

Delivery of ALX-0171 by inhalation greatly reduces respiratory syncytial virus disease in newborn lambs

Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory disease in infants and young children worldwide. Currently, treatment is supportive and no vaccines are available. The use of newborn lambs to model hRSV infection in human infants may provide a valuable tool to assess safety and efficacy of new antiviral drugs and vaccines. ALX-0171 is a trivalent Nanobody targeting the hRSV fusion (F) protein and its therapeutic potential was evaluated in newborn lambs infected with a human strain of RSV followed by daily ALX-0171 nebulization for 3 or 5 consecutive days.

Colostrum-deprived newborn lambs were infected with hRSV-M37 before being treated by daily nebulization with either ALX-0171 or placebo. Two different treatment regimens were examined: day 1–5 or day 3–5 post-infection. Lambs were monitored daily for general well-being and clinical parameters. Respiratory tissues and bronchoalveolar lavage fluid were collected at day 6 post-inoculation for the quantification of viral lesions, lung viral titers, viral antigen and lung histopathology.

Administration by inhalation of ALX-0171 was well-tolerated in these hRSV-infected newborn lambs. Robust antiviral effects and positive effects on hRSV-induced lung lesions and reduction in symptoms of illness were noted. These effects were still apparent when treatment start was delayed and coincided with peak viral loads (day 3 post-infection) and at a time point when signs of RSV disease were apparent. The latter design is expected to have high translational value for planned clinical trials. These results are indicative of the therapeutic potential of ALX-0171 in infants.

Systematic comparison of respiratory syncytial virus-induced memory B cell responses in two anatomical compartments

Respiratory syncytial virus (RSV) is a leading cause of hospitalization in infants and young children. Although it is widely agreed that an RSV vaccine should induce both mucosal and systemic antibody responses, little is known about the B cell response to RSV in mucosa-associated lymphoid tissues. Here, we analyze this response by isolating 806 RSV F-specific antibodies from paired adenoid and peripheral blood samples from 4 young children. Overall, the adenoid-derived antibodies show higher binding affinities and neutralization potencies compared to antibodies isolated from peripheral blood. Approximately 25% of the neutralizing antibodies isolated from adenoids originate from a unique population of IgM⁺ and/or IgD⁺ memory B cells that contain a high load of somatic mutations but lack expression of classical memory B cell markers. Altogether, the results provide insight into the local B cell response to RSV and have implications for the development of vaccines that stimulate potent mucosal responses.

Comparison of risk factors between preterm and term infants hospitalized for severe respiratory syncytial virus in the Russian Federation

Background

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in infants. Preterm birth, in addition to several demographic and environmental factors, increases the risk for development of severe RSV infection. The purpose of this study was to describe differences in risk factors and protective factors between preterm birth (up to 35 weeks’ gestational age) and term infants hospitalized for RSV lower respiratory tract infection in the Russian Federation during the 2008–2009 RSV season.

Methods

Infants up to two years of age hospitalized for a lower respiratory tract infection in Moscow, St Petersburg, and Tomsk were tested for RSV. Patient data, including risk factors and protective factors for RSV, were captured at admission. Differences in these factors were compared between preterm and term patients.

Results

A total of 519 infants hospitalized for lower respiratory tract infection were included in the study. Of these, 197 infants (182 term and 15 preterm) tested positive for RSV. Of all hospitalizations, 51.7% (15/29) of preterm infants versus 37.1% (182/490) of term infants had confirmed RSV (P = 0.118). Among the RSV-positive patients, preterm infants were more likely to have a lower weight at admission (P = 0.050), be of multiple gestation (P < 0.001), have more siblings (P = 0.013), and have more siblings under the age of eight years (P < 0.007) compared with term patients. The preterm infants were less likely to be breastfed (P < 0.001) and more likely to have older mothers (P = 0.050).

Conclusion

Compared with term infants, RSV was a more prevalent cause of hospitalization for lower respiratory tract infection in preterm infants. Of infants hospitalized for RSV, preterm infants were more likely to have additional risk factors for severe RSV. These findings suggest that preterm infants may be exposed to a combination of more strongly interrelated risk factors for severe RSV than term infants.

Epidemiology of respiratory syncytial virus in children ≤2 years of age hospitalized with lower respiratory tract infections in the Russian Federation: a prospective, multicenter study

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infections among infants and young children, and is responsible for an estimated four million deaths per year globally. A monthly injection of palivizumab has been used for prophylaxis of serious RSV infections among high-risk children in 71 countries since 1998 and approval for use in the Russian Federation was obtained in February 2010. A recommendation for RSV prophylaxis in the Russian Federation would require knowledge of the prevalence and seasonality of RSV in that country.

METHODS

In a prospective, multicenter, epidemiological study of the prevalence, seasonality, and peak occurrence of RSV infection, children aged ≤2 years hospitalized for lower respiratory tract infections in three regions of the Russian Federation, from September 2008 through April 2009, were screened and tested for RSV using rapid immunochromatography of nasopharyngeal lavage. For subjects who were tested positive, hospitalization data were collected.

RESULTS

Of 519 children aged ≤2 years enrolled from September 11, 2008 through April 26, 2009, 197 tested positive for RSV (38.0%, 95% CI: 33.8, 42.3). The onset of the 2008-2009 RSV season in the Russian Federation occurred in late October 2008, similar to what is observed in other northern temperate zones. Peak activity occurred in early April 2009, when 62% of children enrolled tested positive for RSV.

CONCLUSION

The prevalence of serious RSV infections in the Russian Federation is similar to the prevalence previously identified in other temperate zones of the northern hemisphere. The seasonality of disease shifted towards early spring, with peak activity later in the season, within a range reported in other countries. These data provide further evidence of serious RSV infection in children in the Russian Federation, as well as guidance for timing of seasonal RSV prophylaxis, especially among individuals at high risk for serious RSV infection.