Respiratory Viral Infections From 2015 to 2022 in the HIVE Cohort of American Households: Incidence, Illness Characteristics, and Seasonality

Abstract

Background: Viral respiratory illnesses are the most common acute illnesses experienced and generally follow a predicted pattern over time. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic interrupted that pattern.

Methods: The HIVE (Household Influenza Vaccine Evaluation) study was established in 2010 to follow a cohort of Southeast Michigan households over time. Initially focused on influenza, surveillance was expanded to include other major respiratory pathogens, and, starting in 2015, the population was followed year round. Symptoms of acute illness were reported, and respiratory specimens were collected and tested to identify viral infections. Based on the known population being followed, virus-specific incidence was calculated.

Results: From 2015 to 2022, 1755 participants were followed in HIVE for 7785 person-years with 7833 illnesses documented. Before the pandemic, rhinovirus (RV) and common cold human coronaviruses (HCoVs) were the viruses most frequently identified, and incidence decreased with increasing age. Type A influenza was next but with comparable incidence by age. Parainfluenza and respiratory syncytial viruses were less frequent overall, followed by human metapneumoviruses. Incidence was highest in young children, but infections were frequently documented in all age groups. Seasonality followed patterns established decades ago. The SARS-CoV-2 pandemic disrupted these patterns, except for RV and, to a lesser extent, HCoVs. In the first 2 years of the pandemic, RV incidence far exceeded that of SARS-CoV-2.

Conclusions: Longitudinal cohort studies are important in comparing the incidence, seasonality, and characteristics of different respiratory viral infections. Studies documented the differential effect of the pandemic on the incidence of respiratory viruses in addition to SARS-CoV-2.

Keywords: SARS-CoV-2; cohort studies; coronaviruses; influenza; respiratory infections.

Figure 1.

Incidence rates by season of selected viruses in the HIVE cohort between 2015 and 2022: (A) rhinovirus; (B) HCoVs and SARS-CoV-2; (C) IAV and IBV; and (D) RSV, HMPV, and HPIVs. Abbreviations: HCoVs, common cold human coronaviruses 229E, NL63, OC43, and HKU1; HMPV, human metapneumovirus; HPIVs, human parainfluenza viruses 1–4; IAV, influenza A virus; IBV, influenza B virus; RSV, respiratory syncytial virus; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. Error bars show the upper confidence limit of the incidence rate.

Figure 2.

Seasonality pre- and postpandemic of selected viruses in the HIVE cohort: (A) rhinovirus; (B) HCoVs and SARS-CoV-2; (C) IAV and IBV; and (D) RSV, HMPV, and HPIVs. Total detections per month have been summed in the prepandemic (2015–2020) and postpandemic (2020–2022) periods to compare cumulative seasonality. Abbreviations: HCoVs, common cold human coronaviruses 229E, NL63, OC43, and HKU1; HMPV, human metapneumovirus; HPIVs, human parainfluenza viruses 1–4; IAV, influenza A virus; IBV, influenza B virus; RSV, respiratory syncytial virus; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.