What are the current common infectious illnesses circulating in the community?

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Last updated: February 21, 2026 • View editorial policy

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Current Common Infectious Illnesses Circulating in the Community

I cannot provide real-time surveillance data on current infectious disease circulation, as the evidence provided consists of historical guidelines (2001-2026) and research studies ending in 2022. However, I can offer evidence-based context about typical seasonal respiratory illness patterns and how they have been disrupted.

Historical Seasonal Patterns (Pre-COVID Era)

Most Common Year-Round Respiratory Pathogens

  • Rhinoviruses are the most frequently identified respiratory pathogen, causing infections throughout the year with peak activity in fall and spring, accounting for the majority of common cold cases 1, 2.
  • Common cold human coronaviruses (not SARS-CoV-2) circulate year-round with winter predominance, representing another leading cause of upper respiratory infections 2.
  • Streptococcus pneumoniae remains a common bacterial cause of community-acquired pneumonia, identified in 9-20% of episodes, though many cases go undiagnosed 1.

Traditional Winter Respiratory Viruses

  • Influenza A and B viruses historically caused predictable winter epidemics in temperate regions, with seasonality driven by temperature, humidity, and indoor crowding 3.
  • Respiratory syncytial virus (RSV) typically peaked in winter months, particularly affecting young children and the elderly 4, 2.
  • Human metapneumovirus, parainfluenza viruses, and adenoviruses followed established seasonal patterns with winter predominance 4, 2.

Pandemic-Era Disruptions (2020-2022 Data)

Dramatic Reductions in Traditional Respiratory Viruses

  • During March 2020, emergency department visits for respiratory complaints initially doubled, but by late 2020, all respiratory conditions (except shortness of breath) accounted for significantly fewer ED visits than pre-pandemic periods 4.
  • Influenza virus, RSV, human parainfluenza virus, adenoviruses, and human metapneumovirus showed markedly lower test positivity in 2020 compared to 2019, likely due to COVID-19 mitigation measures (masking, distancing, hand hygiene) 4.
  • Traditional seasonal patterns were disrupted for most respiratory pathogens except rhinovirus/enterovirus, which maintained relatively normal circulation even during pandemic restrictions 4, 5.

Rhinovirus Persistence

  • Rhinovirus/enterovirus demonstrated higher percent positivity during late 2020 compared to 2019, with ED visits similar to pre-pandemic periods, suggesting these viruses were less affected by mitigation measures 4.
  • In the HIVE cohort study (2015-2022), rhinovirus incidence far exceeded SARS-CoV-2 incidence in the first two pandemic years, highlighting its continued dominance 2.

Post-Mitigation Rebound Concerns

  • Historical seasonal patterns for common respiratory pathogens were disrupted during the SARS-CoV-2 pandemic, with evidence of altered timing and intensity of subsequent outbreaks 5.
  • The differential effect of pandemic mitigation on various respiratory viruses suggests potential for atypical seasonal surges as restrictions ease and population immunity wanes 2.

Clinical Implications

Diagnostic Approach

  • Despite current diagnostic techniques, no pathogen is identified in 40-70% of community-acquired pneumonia cases, emphasizing the importance of empiric treatment based on clinical presentation and risk factors 1.
  • Mixed infections (bacteria + virus or bacteria + atypical pathogen) occur in approximately 3-10% of cases, complicating diagnosis and treatment 1.

Treatment Considerations

  • Empiric treatment should cover the most likely pathogens based on clinical setting and patient risk factors, not on assumptions about current community circulation without local surveillance data 1.
  • For outpatients without cardiopulmonary disease, Streptococcus pneumoniae, Mycoplasma pneumoniae, and Chlamydia pneumoniae remain common causes requiring appropriate antibiotic coverage 1.

Critical Limitations

I cannot answer your question about "new" or currently circulating illnesses because:

  1. The most recent surveillance data provided ends in 2022 4, 2, 5
  2. Respiratory virus circulation patterns remain in flux post-pandemic
  3. Real-time local surveillance is essential for current epidemiologic trends

For accurate current information, consult:

  • Your local public health department's respiratory illness surveillance
  • CDC's weekly FluView and respiratory virus surveillance reports
  • Regional syndromic surveillance systems
  • Hospital-based infection control data in your area

References

1
Guideline

Community-Acquired Pneumonia Etiology

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

3
Research

Seasonality of Respiratory Viral Infections.

Annual review of virology, 2020

4
Research

Changes in Seasonal Respiratory Illnesses in the United States During the Coronavirus Disease 2019 (COVID-19) Pandemic.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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