Comparison of influenza and COVID-19-associated hospitalizations among children < 18 years old in the United States - FluSurv-NET (October-April 2017-2021) and COVID-NET (October 2020-September 2021)

BackgroundInfluenza virus and SARS-CoV-2 are significant causes of respiratory illness in children. MethodsInfluenza and COVID-19-associated hospitalizations among children <18 years old were analyzed from FluSurv-NET and COVID-NET, two population-based surveillance systems with similar catchment areas and methodology. The annual COVID-19-associated hospitalization rate per 100 000 during the ongoing COVID-19 pandemic (October 1, 2020-September 30, 2021) was compared to influenza-associated hospitalization rates during the 2017-18 through 2019-20 influenza seasons. In-hospital outcomes, including intensive care unit (ICU) admission and death, were compared. ResultsAmong children <18 years old, the COVID-19-associated hospitalization rate (48.2) was higher than influenza-associated hospitalization rates: 2017-18 (33.5), 2018-19 (33.8), and 2019-20 (41.7). The COVID-19-associated hospitalization rate was higher among adolescents 12-17 years old (COVID-19: 59.9; influenza range: 12.2-14.1), but similar or lower among children 5-11 (COVID-19: 25.0; influenza range: 24.3-31.7) and 0-4 (COVID-19: 66.8; influenza range: 70.9-91.5) years old. Among children <18 years old, a higher proportion with COVID-19 required ICU admission compared with influenza (26.4% vs 21.6%; p<0.01). Pediatric deaths were uncommon during both COVID-19- and influenza-associated hospitalizations (0.7% vs 0.5%; p=0.28). ConclusionsIn the setting of extensive mitigation measures during the COVID-19 pandemic, the annual COVID-19-associated hospitalization rate during 2020-2021 was higher among adolescents and similar or lower among children <12 years old compared with influenza during the three seasons before the COVID-19 pandemic. COVID-19 adds substantially to the existing burden of pediatric hospitalizations and severe outcomes caused by influenza and other respiratory viruses. SummaryAnnual hospitalization rates and proportions of hospitalized children experiencing severe outcomes were as high or higher for COVID-19 during October 2020-September 2021 compared with influenza during the three seasons before the COVID-19 pandemic, based on U.S. population-based surveillance data.

COVID-19-associated hospitalizations among vaccinated and unvaccinated adults >=18 years - COVID-NET, 13 states, January 1 - July 24, 2021

BackgroundAs of August 21, 2021, >60% of the U.S. population aged [≥]18 years were fully vaccinated with vaccines highly effective in preventing hospitalization due to Coronavirus Disease-2019 (COVID-19). Infection despite full vaccination (vaccine breakthrough) has been reported, but characteristics of those with vaccine breakthrough resulting in hospitalization and relative rates of hospitalization in unvaccinated and vaccinated persons are not well described, including during late June and July 2021 when the highly transmissible Delta variant predominated. MethodsFrom January 1-June 30, 2021, cases defined as adults aged [≥]18 years with laboratory-confirmed Severe Acute Respiratory Coronavirus-2 (SARS-CoV-2) infection were identified from >250 acute care hospitals in the population-based COVID-19-Associated Hospitalization Surveillance Network (COVID-NET). Through chart review for sampled cases, we examine characteristics associated with vaccination breakthrough. From January 24-July 24, 2021, state immunization information system data linked to both >37,000 cases representative cases and the defined surveillance catchment area population were used to compare weekly hospitalization rates in vaccinated and unvaccinated individuals. Unweighted case counts and weighted percentages are presented. ResultsFrom January 1 - June 30, 2021, fully vaccinated cases increased from 1 (0.01%) to 321 (16.1%) per month. Among 4,732 sampled cases, fully vaccinated persons admitted with COVID-19 were older compared with unvaccinated persons (median age 73 years [Interquartile Range (IQR) 65-80] v. 59 years [IQR 48-70]; p<0.001), more likely to have 3 or more underlying medical conditions (201 (70.8%) v. 2,305 (56.1%), respectively; p<0.001) and be residents of long-term care facilities [37 (14.5%) v. 146 (5.5%), respectively; p<0.001]. From January 24 - July 24, 2021, cumulative hospitalization rates were 17 times higher in unvaccinated persons compared with vaccinated persons (423 cases per 100,000 population v. 26 per 100,000 population, respectively); rate ratios were 23, 22 and 13 for those aged 18-49, 50-64, and [≥]65 years respectively. For June 27 - July 24, hospitalization rates were [≥]10 times higher in unvaccinated persons compared with vaccinated persons for all age groups across all weeks. ConclusionPopulation-based hospitalization rates show that unvaccinated adults aged [≥]18 years are 17 times more likely to be hospitalized compared with vaccinated adults. Rates are far higher in unvaccinated persons in all adult age groups, including during a period when the Delta variant was the predominant strain of the SARS-CoV-2 virus. Vaccines continue to play a critical role in preventing serious COVID-19 illness and remain highly effective in preventing COVID-19 hospitalizations.

Utilization of Whole Genome Sequencing to Understand SARS-CoV-2 Transmission Dynamics in Long-Term Care Facilities, Correctional Facilities and Meat Processing Plants in Minnesota, March - June 2020

Congregate settings and high-density workplaces have endured a disproportionate impact from COVID-19. In order to provide further understanding of the transmission patterns of SARS-CoV-2 in these settings, whole genome sequencing (WGS) was performed on samples obtained from 8 selected outbreaks in Minnesota from March - June, 2020. WGS and phylogenetic analysis was conducted on 319 samples, constituting 14.4% of the 2,222 total SARS-CoV-2-positive individuals associated with these outbreaks. Among the sequenced specimens, three LTCFs and both correctional facilities had spread associated with a single genetic sequence. A fourth LTCF had outbreak cases associated with two distinct sequences. In contrast, cases associated with outbreaks in the two meat processing plants represented multiple SARS-CoV-2 sequences. These results suggest that a single introduction of SARS-CoV-2 into a facility can result in a widespread outbreak, and early identification and cohorting of cases, along with continued vigilance with infection prevention and control measures is imperative.

Risk Factors for COVID-19-associated hospitalization: COVID-19-Associated Hospitalization Surveillance Network and Behavioral Risk Factor Surveillance System

BackgroundIdentification of risk factors for COVID-19-associated hospitalization is needed to guide prevention and clinical care. ObjectiveTo examine if age, sex, race/ethnicity, and underlying medical conditions is independently associated with COVID-19-associated hospitalizations. DesignCross-sectional. Setting70 counties within 12 states participating in the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET) and a population-based sample of non-hospitalized adults residing in the COVID-NET catchment area from the Behavioral Risk Factor Surveillance System. ParticipantsU.S. community-dwelling adults ([≥]18 years) with laboratory-confirmed COVID-19-associated hospitalizations, March 1- June 23, 2020. MeasurementsAdjusted rate ratios (aRR) of hospitalization by age, sex, race/ethnicity and underlying medical conditions (hypertension, coronary artery disease, history of stroke, diabetes, obesity [BMI [≥]30 kg/m2], severe obesity [BMI[≥]40 kg/m2], chronic kidney disease, asthma, and chronic obstructive pulmonary disease). ResultsOur sample included 5,416 adults with COVID-19-associated hospitalizations. Adults with (versus without) severe obesity (aRR:4.4; 95%CI: 3.4, 5.7), chronic kidney disease (aRR:4.0; 95%CI: 3.0, 5.2), diabetes (aRR:3.2; 95%CI: 2.5, 4.1), obesity (aRR:2.9; 95%CI: 2.3, 3.5), hypertension (aRR:2.8; 95%CI: 2.3, 3.4), and asthma (aRR:1.4; 95%CI: 1.1, 1.7) had higher rates of hospitalization, after adjusting for age, sex, and race/ethnicity. In models adjusting for the presence of an individual underlying medical condition, higher hospitalization rates were observed for adults [≥]65 years, 45-64 years (versus 18-44 years), males (versus females), and non-Hispanic black and other race/ethnicities (versus non-Hispanic whites). LimitationsInterim analysis limited to hospitalizations with underlying medical condition data. ConclusionOur findings elucidate groups with higher hospitalization risk that may benefit from targeted preventive and therapeutic interventions.