RSV: What the Numbers Show

RSV (Respiratory Syncytial Virus) made headlines in late 2022, calling attention to a vast number of patients flooding inpatient and outpatient settings of care. “RSV is a common respiratory virus that usually causes mild, cold-like symptoms. Most recover in a week or two, but RSV can be serious, especially for infants and older adults.” (CDC) During a one-week period in October, more than 8000 RSV antigen and PCR tests came back positive, according to the CDC, more than double the number of positive tests for the same period last year.

Kythera Labs used our claims database and looked at the spread of RSV across the country during the time period from July 2022 through December 24, 2022. Because of coding disparities and different testing practices, this analysis includes diagnoses typically related to RSV rather than relying on an RSV diagnosis alone. The following diagnoses were used in this analysis: Acute Bronchiolitis Due to RSV, RSV, Acute Bronchitis Due to RSV, and RSV Pneumonia.

While RSV impacts persons of all ages, this analysis focuses on RSV and related respiratory illnesses that impact the younger age cohorts, including those under Age 5, Ages 5-9, and Ages 10-14. 

RSV Began to Appear Earlier In The Calendar Year Than Typically Seen

Like other respiratory viruses, RSV infections typically occur during late fall and early winter. Unlike other years, in 2022, RSV began to appear in late summer and exploded in early fall. Infectious disease experts believe this may be due, in part, to the COVID pandemic, during which people avoided indoor spaces like classrooms, daycare centers, and social activities where children were exposed to common viruses, including RSV, that helped to strengthen their immunity. 


From July 2022 through December 24, 2022, virtually every state had children diagnosed with RSV and RSV- related respiratory illness, and 15% of diagnosed patients required hospitalization.


RSV began to appear in the summer months in the Eastern and South Central states, and as the year progressed, the number of diagnosed cases grew and spread to the Western States later in the year.

The number of patients with select RSV diagnoses grew 582.8% from July to November. The number of States with over 500 RSV-diagnosed patients in the youngest age cohorts grew from 2 states in July to 18 states during the peak in October. The following map shows patients ages 5 through 14, as a percentage of the population in each state, who were diagnosed with RSV and related respiratory illnesses and the spread of RSV over time.

This map shows RSV patients in states over time, with green representing lower numbers and orange representing higher numbers.
  • In August 2022, RSV and related diagnoses continued to impact children in greater numbers across the North and Central part of the country. 14% of patients were hospitalized. 
  • By September 2022, patients with RSV diagnoses were in almost all states, and the number of cases grew 121% from August. 13% of those diagnosed with RSV and related diagnoses were hospitalized, and the virus started to spread West. 
  • By October 2022, there was a 165% increase from the previous month, with 18 states having over 500 patients diagnosed with RSV compared to 6 states with over 500 patients in September. 6% of those diagnosed were hospitalized, and hospitalizations began to decrease in the South and South Central States. 
  • The rate of growth began to decline in November 2022, with a 12.6% increase from the previous month and a slight decrease in the number of states with over 500 patients diagnosed (15 states). 15% of those diagnosed were inpatients, and hospitalizations continued to decrease in the Eastern, Southern and South Central States while increasing in the Western and Southwestern states.
  • Every state had children diagnosed with RSV for the partial month of December (December 1-December 24), with widespread cases in the East, Central and West states. 18% of those diagnosed were hospitalized; however, hospitalizations continued to decrease in the Eastern, Southern and Central States while increasing in the Western and Southwestern states.


For most geographic regions in the U.S., the number of RSV cases has continued to decrease since the end of 2022. This analysis retrospectively looks at the worst months of RSV illness; however, using claims data, one can track cases of illnesses such as RSV or flu in real time. Kythera Labs’ claims database, delivered through Wayfinder, our data science platform, provides easy-to-access, timely, actionable insights for organizations that work to improve patient outcomes. To learn more about our data, Wayfinder, or Kythera Labs, contact us at

*Note: The maps show the number of unique patients diagnosed with RSV or other respiratory diagnoses commonly associated with RSV. The states with darker shading had the highest number of diagnosed patients. The maps are filtered to include only age cohorts Under Age 5, Ages 5-9 and Ages 10-14, and to the following diagnoses: Acute Bronchiolitis Due to RSV, RSV, Acute Bronchitis Due to RSV, and RSV Pneumonia.

RSV: What the Numbers ShowLinkedIn

Lisa Wood

Customer Success & Operations

Lisa, Associated Director of Customer Success and Operations at Kythera Labs, focuses on finding opportunities for efficiency through trend analysis and automation development. Lisa has over 16 years of experience in Healthcare, from payment integrity to Data Analytics & Healthcare Economics, driving collaborative partnerships to support our clients’ utilization of Healthcare big data and application of organization-changing insights.
RSV: What the Numbers ShowLinkedIn

Richa Joshi

Data Analytics
Richa is a Senior Data Analyst at Kythera Labs, supporting strategic initiatives and projects at client organizations and Kythera Labs by analyzing and packaging data. Richa is an analytical problem solver with ten years of Healthcare data experience that includes working with claims, providers, and patient data to help confidently answer business-changing questions.