Saturday, December 02, 2023

ECDC On Increased Mycoplasma Pneumonia Reported In EU/EEA Countries

Credit CDC


While tabloid, social, and even some mainstream media outlets seem determined to present the recent uptick in respiratory illnesses in China - and around the world - as scary precursors to the next pandemic, so far we've seen no indication of anything `novel' at work, or any direct link between China's outbreaks and those being reported in Europe or the United States. 

Admittedly, global surveillance, testing, and data sharing are limited - and new information could change that assessment - but right now we appear to be dealing with an uptick in known, seasonal respiratory illnesses. 

The `Mystery Pneumonia' which has been identified in China and many other countries is by all accounts Mycoplasma pneumoniae, which sparks minor epidemics every few years.  Exact numbers are hard to come by, since this in not a `reportable' disease in most countries, but the CDC estimates:

Estimated incidence

M. pneumoniae infections are common, but the true number of people affected is unknown. An estimated 2 million cases of M. pneumoniae infections occur each year in the United States.

Trends over time

The number of M. pneumoniae infections varies over time, with peaks of disease every 3 to 7 years. This illness can happen any time during the year but may be more common in summer and early fall.


Outbreaks occur mostly in crowded environments like college residence halls and nursing homes. Outbreaks can be prolonged due to the long incubation period of M. pneumoniae.

It is always possible for a new strain to emerge, or one that has increased antibiotic resistance, but so far we haven't seen any reports suggesting either in the EU/EEA or the United States.  

Yesterday the ECDC published their weekly Communicable Disease Threats Report, where they reported on upticks in M. pneumoniae in the EU/EEA in recent months.  

Increase in respiratory infections due to Mycoplasma pneumoniae in the EU/EEA during the season 2023/2024


Epidemics of M. pneumoniae occur periodically, typically every one to three years [1]. Transmission requires close contact with an infected individual, with slow-onset and often atypical respiratory symptoms once infected. Infections typically present with mild, self-remitting upper respiratory tract symptoms; however, patients presenting with prolonged or atypical, severe lower respiratory tract symptoms require antibiotic treatment. 

Six EU/EEA countries have reported recent increases in M. pneumoniae infections at the national level or in specific hospitals. Increases have been reported in all age groups but are predominantly observed in children and adolescents. Additionally, one country observed an increase in severe cases admitted to the intensive care unit.

There are currently no reports of atypical strains or evidence of resistance to first-line macrolide antibiotics.

ECDC assessment:

M. pneumoniae is not notifiable in most EU/EEA countries, leading to limited available information regarding diagnosed cases, proportion of detections amongst respiratory laboratory samples, or historical detection data. As a result, making country-level comparisons should be done with caution. M. pneumoniae epidemics occur cyclically in Europe every one to three years [1]. 

Various factors contribute to this cyclical pattern, such as the decline of population immunity over time or the introduction of new strains into the population. The reported increases are observed following a three-year period of very limited transmission and detection of M. pneumoniae in the EU/EEA, following widespread implementation of non-pharmaceutical measures during the COVID-19 pandemic,resulting in reduced population immunity, particularly amongst those with little or no pre-existing exposures to M. pneumoniae.

There are currently no reports of atypical M. pneumoniae strains or resistance to first-line macrolide antibiotics from reporting countries. However, it remains important for countries to monitor and report the occurrence of atypical and/or severe forms of disease, evidence of resistance to antibiotics, and strains on the healthcare system related to M. pneumoniae cases as winter progresses and the combined burden of respiratory pathogens increase.


ECDC continues to monitor the situation. Countries are encouraged to continue reporting to EpiPulse with additional information: 2023-IRV-00008. In particular, countries with laboratory systems that routinely screen respiratory samples for M. pneumoniae are encouraged to report current and historic trend data for detections, as well as strain characterisation and antibiotic susceptibility data, if available

Not surprisingly, we are also seeing reports of sporadic outbreaks here in the United States (see Warren Ohio Health Dept. Press Release), and additional outbreaks are to be expected. While there doesn't appear to be anything `novel' about these outbreaks, that doesn't make them benign. 

The CDC advises:

People at Risk 

Mycoplasma pneumoniae infections are most common in young adults and school-aged children, but can affect anyone. People living and working in crowded settings are at increased risk. These settings include:
  • Schools
  • College residence halls
  • Military training facilities
  • Long-term care facilities
  • Hospitals
Other people at increased risk for serious infections include those:
  • Recovering from a respiratory illness
  • With a weakened immune system

Help protect yourself and others from Mycoplasma pneumoniae infection by practicing good hand hygiene.

People can get infected with Mycoplasma pneumoniae more than once. While there is no vaccine to prevent M. pneumoniae infections, there are things people can do to protect themselves and others.

Good hygiene

Like many respiratory germs, Mycoplasma pneumoniae most commonly spread by coughing and sneezing. Some tips to prevent the spread of M. pneumoniae include:
Cover your mouth and nose with a tissue when you cough or sneeze.
  • Put your used tissue in a waste basket.
  • If you don’t have a tissue, cough or sneeze into your upper sleeve or elbow, not your hands.
  • Wash your hands often with soap and water for at least 20 seconds.
  • If soap and water are not available, use an alcohol-based hand rub.
Preventive antibiotics

Doctors generally do not prescribe antibiotics to help prevent someone else from getting sick (for example, a close contact of an infected person).

Mycoplasma pnuemoniae infections are generally mild, but some people may need care in a hospital.

Most people will recover from an infection caused by Mycoplasma pneumoniae without antibiotics. Ask your doctor or pharmacist about over-the-counter medicines that can help you feel better while you are recovering.

However, if someone develops pneumonia (lung infection) caused by M. pneumoniae, doctors usually prescribe antibiotics. There are several types of antibiotics available to treat pneumonia caused by M. pneumoniae. Antibiotics can help patients recover from the infection faster if started early on.

Some M. pneumoniae are resistant to some antibiotics used for treatment. Learn more about the potential danger of antibiotic resistance, and how to prevent it at CDC’s Be Antibiotics Aware website.


While M. pneumoniae usually cause mild infections, severe complications can occur that require care in a hospital. M. pneumoniae infections can cause or worsen the following complications:
  • Serious pneumonia
  • Asthma attacks or new asthma symptoms
  • Encephalitis (swelling of the brain)
  • Hemolytic anemia (too few red blood cells, which means fewer cells to deliver oxygen in the body)
  • Renal dysfunction (kidney problems)
  • Skin disorders like Stevens-Johnson syndrome, erythema multiforme, toxic epidermal necrolysis

We are entering what is likely to be a messy winter respiratory season, with a mixture of influenza viruses, COVID, RSV, adenoviruses, rhinoviruses, and bacterial pneumonia. 

Some can be reduced by vaccines, while others are susceptible to non-pharmaceutical measures like hand hygiene and face masks. 

As always . . .