Surge in Mycoplasma Pneumonia Linked to Reduced Mask-Wearing

Cases of mycoplasma pneumonia are escalating significantly. Because of its lengthy incubation period and potential for asymptomatic transmission, it is often called "walking pneumonia."

According to the National Institute of Infectious Diseases, the weekly average number of cases per medical institution nationwide has been rising. As of August 20, this increase marks the sixth consecutive week. The average has now climbed to 1.14 individuals.

This figure represents a 57-fold increase over the same period last year and is the highest recorded in the past decade. Experts suggest that "the decline in mask-wearing could be contributing to the spread of this disease." Masks were a key preventive measure during the COVID-19 pandemic.

Persistent Cough as a Distinctive Symptom

Mycoplasma pneumonia is transmitted through respiratory droplets and direct physical contact. It manifests symptoms similar to those of a cold, including fever, cough, and fatigue. While the disease predominantly affects children under 14—accounting for about 80% of cases—it can also affect adults.

Most cases are mild, but the disease is characterized by a persistent cough that can sometimes lead to serious complications. Due to its prolonged incubation period of two to three weeks, individuals may spread the infection unknowingly. Many also recover without treatment, hence the nickname "walking pneumonia."

Pneumonia Shift

Dr Kenzo Takahashi is a pediatrician and professor at Teikyo University Graduate School. Discussing this year's outbreak expansion, he highlighted a shift in the affected demographic. "Since before the May holidays, there has been a noticeable uptick in cases among adolescents, especially middle school students," he observed. This is in contrast to the lower numbers seen in younger children.

He further explained the typical symptoms, saying, "Many patients initially confuse their symptoms of cough and fever with COVID-19. However, when the fever persists, they seek medical attention." Furthermore, as he points out, "the condition often resembles bronchial pneumonia rather than full pneumonia. There are also cases where a mild fever escalates to severe coughing, which subsequently spreads the disease among family members."

Outbreaks of mycoplasma pneumonia typically occur globally every three to seven years and are often noted to coincide with Olympic years. Nonetheless, no outbreaks were observed during the COVID-19 period.

Takahashi attributes this year's significant spread of mycoplasma pneumonia to the prior COVID precautions. "The stringent COVID measures prevented any outbreaks of mycoplasma pneumonia," he states. "These measures likely resulted in a lower overall community immunity." Additionally, the 2023 downgrade of COVID-19 and reduced mask-wearing created conditions for mycoplasma pneumonia to resurge, leading to the outbreak. "It's crucial that we remain vigilant about prevention," Takahashi cautions.

*A woman receives a COVID-19 vaccination on September 20, 2023. (©Sankei by Takaki Rikitake)*

Antibiotic Shortage Adds to Treatment Challenge

Preventive measures like those used during the COVID-19 pandemic—such as mask-wearing, frequent handwashing, and using alcohol-based disinfectants—are considered sufficient. However, treatment complexities arise, as Dr Takahashi points out. "Natural recovery is often possible, but persistent fevers may necessitate the use of antibiotics," he says. "Macrolide antibiotics are typically effective," Takahashi advises. "However, there has been an increase in resistance. This means patients must use quinolone or tetracycline antibiotics to effectively manage the fever."

Compounding the treatment challenge is an ongoing antibiotic shortage that began last summer. Pharmacies have subsequently had to share their supplies at times. Takahashi emphasizes that antibiotics are not particularly effective for treating coughs and urges healthcare professionals to refrain from over-prescribing them. "To ensure that patients who truly need them can access them, it is important to avoid prescribing them 'just in case,''' he suggests.

Read the article in Japanese.

Author: Tomoko Iizuka