Respiratory Syncytial Virus-Associated Hospitalizations Among Adults With Chronic Medical Conditions

BACKGROUND

In contrast with respiratory disease caused by influenza, information on the risk of respiratory syncytial virus (RSV) disease among adults with chronic medical conditions (CMCs) is limited.

METHODS

We linked population-based surveillance of acute respiratory illness hospitalizations to national administrative data to estimate seasonal RSV hospitalization rates among adults aged 18-80 years with the following preexisting CMCs: chronic obstructive pulmonary disease (COPD), asthma, congestive heart failure (CHF), coronary artery disease (CAD), cerebrovascular accidents (CVA), diabetes mellitus (DM), and end-stage renal disease (ESRD). Age- and ethnicity-adjusted rates stratified by age group were estimated.

RESULTS

Among 883 999 adult residents aged 18-80 years, 281 RSV-positive hospitalizations were detected during 2012-2015 winter seasons. Across all ages, RSV hospitalization rates were significantly higher among adults with COPD, asthma, CHF, and CAD compared with those without each corresponding condition. RSV hospitalization rates were significantly higher among adults with ESRD aged 50-64 years and adults with DM aged 18-49 years and 65-80 years compared with adults in each age group without these conditions. No increased risk was seen for adults with CVA. The CMC with the highest risk of RSV hospitalization was CHF (incidence rate ratio [IRR] range, 4.6-36.5 across age strata) and COPD (IRR range, 9.6-9.7). Among RSV-positive adults, CHF and COPD were independently associated with increased length of hospital stay.

CONCLUSIONS

Adults with specific CMCs are at increased risk of RSV hospitalizations. Age affects this relationship for some CMCs. Such populations maybe relevant for future RSV prevention strategies.

Modelling the impact of respiratory syncytial virus (RSV) vaccine and immunoprophylaxis strategies in New Zealand

BACKGROUND

Mathematical models of respiratory syncytial virus (RSV) transmission can help describe seasonal epidemics and assess the impact of potential vaccines and immunoprophylaxis with monoclonal antibodies (mAb).

METHODS

We developed a deterministic, compartmental model for RSV transmission, which was fitted to population-based RSV hospital surveillance data from Auckland, New Zealand. The model simulated the introduction of either a maternal vaccine or a seasonal mAb among infants aged less than 6 months and estimated the reduction in RSV hospitalizations for a range of effectiveness and coverage values.

RESULTS

The model accurately reproduced the annual seasonality of RSV epidemics in Auckland. We found that a maternal vaccine with effectiveness of 30-40% in the first 90 days and 15-20% for the next 90 days could reduce RSV hospitalizations by 18-24% in children younger than 3 months, by 11-14% in children aged 3-5 months, and by 2-3% in children aged 6-23 months. A seasonal infant mAb with 40-60% effectiveness for 150 days could reduce RSV hospitalizations by 30-43%, 34-48% and by 14-21% in children aged 0-2 months, 3-5 months and 6-23 months, respectively.

CONCLUSIONS

Our results suggest that either a maternal RSV vaccine or mAb would effectively reduce RSV hospitalization disease burden in New Zealand. Overall, a seasonal mAb resulted in a larger disease prevention impact than a maternal vaccine.

Respiratory Syncytial Virus Vaccination during Pregnancy and Effects in Infants

BACKGROUND

Respiratory syncytial virus (RSV) is the dominant cause of severe lower respiratory tract infection in infants, with the most severe cases concentrated among younger infants.

METHODS

Healthy pregnant women, at 28 weeks 0 days through 36 weeks 0 days of gestation, with an expected delivery date near the start of the RSV season, were randomly assigned in an overall ratio of approximately 2:1 to receive a single intramuscular dose of RSV fusion (F) protein nanoparticle vaccine or placebo. Infants were followed for 180 days to assess outcomes related to lower respiratory tract infection and for 364 days to assess safety. The primary end point was RSV-associated, medically significant lower respiratory tract infection up to 90 days of life, and the primary analysis of vaccine efficacy against the primary end point was performed in the per-protocol population of infants (prespecified criterion for success, lower bound of the 97.52% confidence interval [CI] of ≥30%).

RESULTS

A total of 4636 women underwent randomization, and there were 4579 live births. During the first 90 days of life, the percentage of infants with RSV-associated, medically significant lower respiratory tract infection was 1.5% in the vaccine group and 2.4% in the placebo group (vaccine efficacy, 39.4%; 97.52% CI, -1.0 to 63.7; 95% CI, 5.3 to 61.2). The corresponding percentages for RSV-associated lower respiratory tract infection with severe hypoxemia were 0.5% and 1.0% (vaccine efficacy, 48.3%; 95% CI, -8.2 to 75.3), and the percentages for hospitalization for RSV-associated lower respiratory tract infection were 2.1% and 3.7% (vaccine efficacy, 44.4%; 95% CI, 19.6 to 61.5). Local injection-site reactions among the women were more common with vaccine than with placebo (40.7% vs. 9.9%), but the percentages of participants who had other adverse events were similar in the two groups.

CONCLUSIONS

RSV F protein nanoparticle vaccination in pregnant women did not meet the prespecified success criterion for efficacy against RSV-associated, medically significant lower respiratory tract infection in infants up to 90 days of life. The suggestion of a possible benefit with respect to other end-point events involving RSV-associated respiratory disease in infants warrants further study. (Funded by Novavax and the Bill and Melinda Gates Foundation; ClinicalTrials.gov NCT02624947.).

The health and economic burden of respiratory syncytial virus associated hospitalizations in adults

Background

Respiratory syncytial virus (RSV) is increasingly recognized as an important cause of illness in adults; however, data on RSV disease and economic burden in this age group remain limited. We aimed to provide comprehensive estimates of RSV disease burden among adults aged ≥18 years.

Methods

During 2012–2015, population-based, active surveillance of acute respiratory infection (ARI) hospitalizations enabled estimation of the seasonal incidence of RSV hospitalizations and direct health costs in adults aged ≥18 years in Auckland, New Zealand.

Results

Of 4,600 ARI hospitalizations tested for RSV, 348 (7.6%) were RSV positive. The median (interquartile range) length of hospital stay for RSV positive patients was 4 (2–6) days. The seasonal incidence rate (IR) of RSV hospitalizations, corrected for non-testing, was 23.6 (95% confidence intervals [CI] 21.0–26.1) per 100,000 adults aged ≥18 years. Hospitalization risk increased with age with the highest incidence among adults aged ≥80 years (IR 190.8 per 100,000, 95% CI 137.6–244.0). Being of Māori or Pacific ethnicity or living in a neighborhood with low socioeconomic status (SES) were independently associated with increased RSV hospitalization rates. We estimate RSV-associated hospitalizations among adults aged ≥18 years to cost on average NZD $4,758 per event.

Conclusions

RSV infection is associated with considerable disease and economic cost in adults. RSV disproportionally affects adult sub-groups defined by age, ethnicity, and neighborhood SES. An effective RSV vaccine or RSV treatment may offer benefits for older adults.

Respiratory virus detection during hospitalisation for lower respiratory tract infection in children under 2 years in South Auckland, New Zealand

AIM

To describe respiratory virus detection in children under 2 years of age in a population admitted with lower respiratory infection and to assess correlation with measures of severity.

METHODS

Nasopharyngeal aspirates from infants admitted with lower respiratory tract infection (n = 1645) over a 3-year time period were tested by polymerase chain reaction. We collected epidemiological and clinical data on all children. We assessed the correlation of presence of virus with length of hospital stay, intensive care admission and consolidation on chest X-ray.

RESULTS

Of the children admitted 34% were Maori, 43% Pacific and 75% lived in areas in the bottom quintile for socio-economic deprivation. A virus was found in 94% of those tested including 30% with multiple viruses. Picornavirus was present in 59% including 34% as the sole virus. Respiratory syncytial virus was found in 39%. Virus co-detection was not associated with length of stay, chest X-ray changes or intensive care unit admission.

CONCLUSION

In this disadvantaged predominately Maori and Pacific population, picornavirus is commonly found as a sole virus, respiratory syncytial virus is frequent but immunisation preventable influenza is infrequent. We did not find that co-detection of viruses was linked to severity.

Respiratory health outcomes 1 year after admission with severe lower respiratory tract infection

Severe lower respiratory infection (LRI) is believed to be one precursor of protracted bacterial bronchitis, chronic moist cough (CMC), and chronic suppurative lung disease. The aim of this study was to determine and to describe the presence of respiratory morbidity in young children 1 year after being hospitalized with a severe LRI. Children aged less than 2 years admitted from August 1, 2007 to December 23, 2007 already enrolled in a prospective epidemiology study (n = 394) were included in this second study only if they had a diagnosis of severe bronchiolitis or of pneumonia with no co-morbidities (n = 237). Funding allowed 164 to be identified chronologically, 131 were able to be contacted, and 94 agreed to be assessed by a paediatrician 1 year post index admission. Demographic information, medical history and a respiratory questionnaire was recorded, examination, pulse oximetry, and chest X-ray (CXR) were performed. The predetermined primary endpoints were; (i) history of CMC for at least 3 months, (ii) the presence of moist cough and/or crackles on examination in clinic, and (iii) an abnormal CXR when seen at a time of stability. Each CXR was read by two pediatric radiologists blind to the individuals' current health. Results showed 30% had a history of CMC, 32% had a moist cough and/or crackles on examination in clinic, and in 62% of those with a CXR it was abnormal. Of the 81 children with a readable follow-up X-ray, 11% had all three abnormal outcomes, and 74% had one or more abnormal outcomes. Three children had developed bronchiectasis on HRCT. The majority of children with a hospital admission at <2 years of age for severe bronchiolitis or pneumonia continued to have respiratory morbidity 1 year later when seen at a time of stability, with a small number already having sustained significant lung disease.

Impact of pneumococcal vaccine on hospital admission with lower respiratory infection in children resident in South Auckland, New Zealand

AIM

To assess the change in admission rates for all Lower Respiratory Infection (LRI) including pneumonia for children resident in Counties Manukau District Health Board (CMDHB) with the introduction of the Pneumococcal Conjugate Vaccine 7 valent (PCV7) in June 2008.

METHOD

National Minimum dataset ICD10 coded LRI admissions to any NZ hospital August 2001-July 2011 for children <2 year resident in CMDHB were analysed using Poisson regression, omitting 1 August 2008 to 31 July 2009, the first-year post vaccine introduction.

RESULTS

Pneumonia but not bronchiolitis admissions have been declining since 2001. Pneumonia admissions decreased significantly after PCV7 introduction (incidence risk ratio (IRR) (95% CI) 1.51 (1.08-1.77), additional to the gradual decline since 2001. There was significant decline for Pacific children post PCV7 introduction IRR 1.70(1.39, 2.07) but not for Maori children, IRR 1.05 (0.78-1.40). Maori and Pacific children are at increased risk of admission with LRI compared to European children (relative risk (RR) (95%CI) 4.6 (4.3-5.0) and 5.0(3.7-5.3) respectively) as are those living in Decile 9, 10 compared with those from other deciles, RR 1.43 (1.36-1.50).

CONCLUSION

The introduction of PCV7 is associated with reduced admissions for pneumonia in young children yet there has been less impact for Maori in CMDHB.

Kawasaki disease in Auckland, 1979-1988

Records of 34 children diagnosed as having Kawasaki disease in the Auckland region from 1979 to 1988 inclusive were reviewed. Diagnostic and associated features were similar to those reported from North America and Japan. The incidence (average 5.1 per year per 100,000 less than 5 years of age) was similar to that reported in Europe and North America amongst nonorientals and was similar in Polynesians and nonPolynesians. Coronary artery abnormalities were found in five cases (15%), and two cases, both of whom presented before five months of age, died. Those with abnormal coronary arteries had fever for a significantly longer period than those with normal coronary arteries.