Mycoplasma pneumoniae Infection Surveillance and Trends

Key points

  • There is no national reporting or surveillance system for Mycoplasma pneumoniae infections.
  • M. pneumoniae infections are common.
  • These infections may occur more often in summer and early fall.
  • So far in 2024, CDC has seen an increase in M. pneumoniae infections.
An illustration of generic data

Data sources

A M. pneumoniae infection isn't a nationally notifiable condition. This means that healthcare providers aren't required to report infections to their local public health department. However, CDC can monitor national trends using syndromic and commercial laboratory data collected by:

To understand the epidemiology of M. pneumoniae infections, researchers collect additional data from:

Studies

M. pneumoniae infections are common in the United States, with an estimated 2 million infections occurring each year12. However, many infections aren't diagnosed, so the actual number is likely higher.

Outbreaks

Outbreaks occur mostly in crowded environments like schools, college residence halls, and nursing homes.

Outbreaks can be prolonged due to the long incubation period of M. pneumoniae.

Trends

The number of M. pneumoniae infections varies over time. There are usually peaks of disease every 3 to 7 years13. Variation in strain types contributes to this pattern. In 2023, M. pneumoniae began to re-emerge globally. This re-emergence occurred after a prolonged period of low incidence of infections since the start of the COVID-19 pandemic.

M. pneumoniae infections can occur any time of the year. However, they may be more common in summer and early fall3.

2024 activity

So far in 2024, CDC has seen an increase in M. pneumoniae infections, including in young children. This differs from previous years in which most infections were observed among older children and adolescents. Data from NSSP, NVSN, and BIOFIRE® all indicate that M. pneumoniae infections began increasing in late spring/early summer of 2024. This increase is from a low baseline observed since the start of the COVID-19 pandemic.

CDC is continuing to track this increase to better understand any differences in:

  • Demographics
  • Severity of illness (including skin disorders)
  • Outcomes as compared to M. pneumoniae infections prior to the COVID-19 pandemic

Increases in emergency department visits

CDC looked at NSSP data for the percent of pneumonia-associated emergency department visits with a Mycoplasma-related diagnostic code.

From the week ending April 6, 2024 through the week ending August 31, 2024, these emergency department visits increased from:

  • All ages: 0.5% to 1.8%
  • 2–4-year-olds: 1.0% to 7.3%
  • 5–17-year-olds: 3.6% to 8.0%

The increase in 2–4-year-olds is notable because these infections have historically been thought to affect school-age more than younger children.

Antibiotic resistance

CDC is tracking resistance to macrolides among M. pneumoniae causing infections. Monitoring occurs by testing specimens submitted by local and state public health departments and from surveillance systems.

Resistance to macrolides emerged in M. pneumoniae and has been increasing since the early 2000s45. Macrolides are the main type of antibiotic used to treat M. pneumoniae infections.

Current data suggest that the overall global prevalence of macrolide resistance in M. pneumoniae may be around 28%4. However, there's significant geographical variation4:

  • Canada: About 12%
  • China: About 80%
  • Europe: Averages around 5% (highest in Italy: 20%)
  • Japan: More than 50%
  • United States: Less than 10% overall; limited data show higher proportions (>20%) observed67in:
    • The South and East
    • Within clusters or outbreaks prior to the COVID-19 pandemic
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Content Source:
National Center for Immunization and Respiratory Diseases; Division of Bacterial Diseases
  1. Diaz M, Benitez A, Winchell J. Investigations of Mycoplasma pneumoniae infections in the United States: Trends in molecular typing and macrolide resistance from 2006 to 2013. J Clin Microbiol. 2015;53(1):124–30.
  2. Jain S, Williams D, Arnold S, et al. Community-acquired pneumonia requiring hospitalization among U.S. children. NEJM. 2015;372:835–45.
  3. Foy HM. Infections caused by Mycoplasma pneumoniae and possible carrier state in different populations of patients. Clin Infect Dis. 1993;17(Supplement_1):S37–S46.
  4. Kim K, Jung S, Kim M, et al. Global trends in the proportion of macrolide-resistant Mycoplasma pneumoniae infections: A systematic review and meta-analysis. JAMA Netw Open. 2022;5(7):e2220949.
  5. Rothstein TE, Cunningham SA, Rieke RA, Mainella JM, Mutchler MM, Patel R. Macrolide resistance in Mycoplasma pneumoniae, Midwestern United States, 2014 to 2021. Antimicrob Agents Chemother. 2022;66(4):e0243221.
  6. Waites KB, Ratliff A, Crabb DM, Xiao L, Qin X, Selvarangan R, Tang YW, Zheng X, Dien Bard J, Hong T, Prichard M, Brooks E, Dallas S, Duffy L, Mixon E, Fowler KB, Atkinson TP. Macrolide-resistant Mycoplasma pneumoniae in the United States as determined from a national surveillance program. J Clin Microbiol. 2019;57(11):e00968–19.
  7. Diaz MH, Benitez AJ, Winchell JM. Investigations of Mycoplasma pneumoniae infections in the United States: Trends in molecular typing and macrolide resistance from 2006 to 2013. J Clin Microbiol. 2015;53(1):124–30.