Background Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infections (ARI) in hospitalized children. Although prematurity and underlying medical conditions are known risk factors, most of these children are healthy, and factors including RSV load and subgroups may contribute to RSV-ARI severity. Therefore, we aimed to evaluate the role of RSV in ARI disease severity and determine factors associated with increased RSV-ARI severity in young children. Method Children less than five years with fever and/or ARI symptoms were recruited from the emergency department (ED) or inpatient settings at Vanderbilt Children's Hospital. Nasal and/or throat swabs were tested by qRT-PCR for common respiratory viruses, including RSV. A severity score was calculated for RSV-positive children. Results From 11/2015 through 07/2016, 898 participants were enrolled, and 681 (76%) had at least one virus detected, with 191 (28%) testing positive for RSV. RSV-positive children were more likely to be hospitalized, require intensive care unit (ICU) admission, and receive oxygen compared to other-virus-positive children. Higher viral load, White race, younger age, and higher severity score were independently associated with hospitalization in RSV-positive children. No differences in disease severity were noted among children infected with RSV A and B. Conclusion RSV was associated with increased ARI severity in young children enrolled from ED and inpatient settings, but no differences in disease severity were noted between RSV A and B. . These findings emphasize the need for effective antiviral therapy and/or preventive measures such as vaccines against RSV in young children.

Increasing use of immunosuppressive biologic therapies poses a challenge for infectious diseases. Immunosuppressed patients have a high risk for influenza complications and an impaired immune response to vaccines. The total burden of immunosuppressive conditions in the United States, including those receiving emerging biologic therapies, remains unknown. We used the national claims database MarketScan to estimate the prevalence of immunosuppressive conditions and risk for acute respiratory illnesses (ARIs). We studied 47.2 million unique enrollees, representing 115 million person-years of observation during 2012–2017, and identified immunosuppressive conditions in 6.2% adults 18–64 years of age and 2.6% of children <18 years of age. Among 542,105 ARI hospitalizations, 32% of patients had immunosuppressive conditions. The risk for ARI hospitalizations was higher among enrollees with immunosuppression than among nonimmunosuppressed enrollees. Future efforts should focus on developing improved strategies, including vaccines, for preventing influenza in immunosuppressed patients, who are an increasing population in the United States.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased morbidity and mortality in solid organ transplant (SOT) recipients. Despite exclusion from SARS-CoV-2 vaccine clinical trials, these individuals were identified as high-risk and prioritized for vaccination in public health guidelines. Methods:We prospectively evaluated humoral and cellular immune responses to two doses of the SARS-CoV-2 mRNA vaccine, BNT162b2, in 56 SOT recipients and 26 healthy controls (HCs). Blood specimens collected from participants prior to each dose and following the second dose were tested for SARS-CoV-2-specific antibodies, as well as CD4+ and CD8+ T-cell responses.Results: SOT recipients demonstrated lower mean anti-SARS-CoV-2 antibody levels compared to HCs after each dose, and only 21.6% achieved an antibody response after the second dose within the range of HC responses. Similarly, the percentage of responsive CD4+ and CD8+ T cells in SOT recipients was lower than in HCs. While most HCs showed notable humoral and cellular responses, responses were less concordant in

Purpose of review To review the epidemiological characteristics and clinical features associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among children in the United States. Recent findings In the United States, the majority of SARS-CoV-2 infections in children have been mild illnesses, with those 5–17 years of age having the highest frequency. Specifically, the incidence of SARS-CoV-2 in children is two times higher in adolescents (12–17 years) than younger school-aged children (5–11 years). Despite the higher case counts in older children, 10% of pediatric hospitalizations have been in infants less than one year. In addition, severe respiratory and renal complications, hospitalization, and even death have been documented in children. Summary Clinical manifestations of SARS-CoV-2 infection in children range from asymptomatic to severe respiratory distress, with mild nonspecific symptoms being the most commonly reported. The broad clinical presentation and the frequency of asymptomatic or minimally symptomatic infections in children pose challenges for controlling and detecting SARS-CoV-2. However, severe disease has been noted in children with associated medical complications and death. Thus, additional active surveillance and research is needed to understand the burden children contribute to the SARS-CoV-2 pandemic in the United States.