The Mainichi Shimbun answers some common questions readers may have about why the common cold will be classified as "category 5" under Japan's infectious disease control law -- the same level as seasonal flu and COVID-19 -- and what changes this will bring. This reclassification has been a hot topic on social media, but there are also some misunderstandings. How will this affect our daily lives?

Question: Is the common cold becoming a "category 5" disease?

Answer: To be precise, it refers to the classification of acute respiratory infections (ARI), which include the common cold, as category 5. ARI is a general term for diseases caused by pathogens that lead to upper respiratory tract infections like rhinitis (runny nose and sneezing) and sinusitis (inflamed sinuses), and lower respiratory tract infections like bronchitis and pneumonia. Category 5 diseases also include COVID-19, influenza, respiratory syncytial virus infections, and pharyngoconjunctival fever.

Q: Why will ARI be classified as category 5?

A: ARI is easily transmissible through droplets. Classifying it as category 5, the same as coronavirus and flu infections, allows for monitoring domestic cases even during normal times. It is expected to enable a swift response to emergencies such as pandemics by quickly detecting the emergence of unknown infectious diseases, like when the coronavirus began to spread.

Q: How will ARI be monitored?

A: Starting April 7, 2025, approximately 3,000 fixed-point medical institutions across the country will report the number of patients weekly. The report will include patients with symptoms like cough, sore throat, runny nose or nasal congestion, within 10 days of onset. Cases that do not fit known diseases like COVID-19 or are common colds will also be reported as "others." Additionally, around 300 medical institutions will provide samples from patients for pathogen analysis.

Q: What impact will this have on our lives?

A: Unlike before the legal status of COVID-19 was downgraded to category 5 in 2023, there will be no requests for people with colds to refrain from going out. There will be no work restrictions or school attendance suspensions. The co-payment of medical expenses will remain the same. Current laws do not mandate inoculation, including the COVID-19 vaccine, although there is a misconception spreading on social media about a "mandatory cold vaccine." Apart from the burden on medical institutions required to report cases, there will be no impact on patients.

(Japanese original by Naohiro Koenuma, Lifestyle, Science & Environment News Department)