Positive Health Online

In the weeks following the start of the kindergarten and school year, the number of respiratory infections among children increases significantly. Although many people suspect that this is due to a weakened immune system, the main factors are the return to group settings, indoor environments, changes in daily routines, and the easier and faster spread of viruses. However, adequate sleep, hand hygiene, regular ventilation, and vaccinations can go a long way toward prevention.

https://semmelweis.hu/english/2026/08/kids-dont-get-sick-in-the-fall-because-their-immune-systems-are-weakened/

Dr Laura Kossuth, a specialist at Semmelweis University’s Pediatric Center

Every year in September, the number of respiratory infections in kindergartens and schools increases significantly. Many people believe this is due to children’s weakened immune systems by the end of summer, but the real explanation is that large numbers of children return to their group settings all at once. “While children spend more time outdoors in smaller groups during vacation and are less frequently in crowded, enclosed spaces, the start of kindergarten and school results in a sharp rise in the number of close contacts, which facilitates the spread of respiratory viruses,” says Dr Laura Kossuth, a specialist at Semmelweis University’s Pediatric Center.

After the summer break, children’s bodies undergo several changes: They have to wake up earlier, often get less sleep, their daily routines change, and for many of them, returning to a group setting can also be emotionally stressful. In addition, eating habits may alter, time spent outdoors may decrease, and they are exposed to many new pathogens. These changes do not in themselves weaken the immune system. The higher frequency of infections is primarily due to the growing number of contacts within the community and increased exposure to pathogens, while adequate sleep and a balanced daily routine support the optimal functioning of the body.

During the period when children start kindergarten and school, a variety of respiratory viruses can cause illness, and in the fall and winter months, RSV (respiratory syncytial virus) and the influenza virus may also play an increasingly significant role. The expert emphasizes that, based on the symptoms, it is often impossible to determine exactly which virus is responsible since a runny nose, a cough, a sore throat, fatigue, loss of appetite, or fever can manifest similarly across multiple infections. In such cases, symptom-checking and decision-support tools such as Semmelweis HELP, which was developed by the university and is available free of charge, can be a great help to families. It assists in determining how quickly to see a doctor in the event of an illness or accident, and the platform also provides information on proper methods for relieving symptoms. Since illnesses in early fall are predominantly viral in origin, antibiotics are generally not necessary; their use is warranted only in cases of bacterial infection.

Dr Laura Kossuth also calls attention to the misconception that the more infections a child goes through, the stronger their immune system will become. Although the immune system develops and is capable of building immunological memory after exposure to certain pathogens or vaccines, respiratory viruses are extremely diverse and mutate rapidly. Therefore, frequent illnesses do not offer any advantage, and vaccines provide safer protection against preventable infections.

https://semmelweis.hu/english/2026/08/we-can-eat-bread-several-times-a-day-as-long-as-it-is-wholegrain/

Students can eat bread several times per day, as long as it is wholegrain

There is no guaranteed way to prevent infections completely, but parents can do a lot to ensure their children start the school year well-prepared. The most important factors are getting enough sleep, eating a varied diet, exercising regularly, staying well-hydrated, and spending time outdoors. It is also essential that children learn proper handwashing techniques, coughing and sneezing etiquette, and not to share each other’s water bottles or flatware. Regular ventilation of classrooms can also help reduce the spread of respiratory viruses. “In the fall, it is also worth paying attention to adequate vitamin D intake since vitamin D production from sunlight decreases during this season. At the same time, this should not be considered an ‘immune booster’ either that, on its own, prevents infections at kindergarten or school. It is always a good idea to consult with your child’s paediatrician about the appropriate dosage,” the expert recommends.

Parents should not base their decision on whether their sick child can go to a group setting solely on a runny nose or a cough. The most important factor in every case is the child’s overall condition: If they have a fever, are lethargic, or unable to participate in daily activities, then they need rest and care at home. If, on the other hand, they are in good spirits, fever-free, and able to handle physical activity, a mild cold alone does not necessarily justify keeping them away from kindergarten or school for an extended period – provided, of course, that the institution’s epidemiological and absence policies are also taken into account.

https://semmelweis.hu/english/files/2024/04/Semmelweis-University-brochure-2023.pdf

About the Author

Balázs Csizmadia has a background in the humanities (literature, translation, language testing, language teaching), useful experience in foreign countries (Switzerland, UK, Norway), full professional proficiency in English and German, confident presentation, team coordination as well as computer skills (Excel, Word, PowerPoint, etc.), and a basic knowledge of statistics. His colleagues and clients have always praised his accuracy, thoroughness and reliability, as well as appreciating his ability to communicate my knowledge in a clear and comprehensible way. He is eager to learn new skills and can do so easily, both in his work and as far as hobbies are concerned. He is interested in learning about new possibilities offered by artificial intelligence (AI), especially its linguistic aspects.  Semmelweis University Central administration address and phone number: H - 1085 Budapest, Üllői út 26.   +36 1 459-1500 | +36-20-825-1000. Balázs Csizmadia’s  profile is published at https://www.linkedin.com/in/balazscsizmadia/

Further Information and Acknowledgement Citation

Semmelweis HELP is a free, Hungarian-language symptom-checking, decision-support tool that helps users determine whether they should go to the emergency room, a hospital, or a specialist in the event of an illness or accident, or how to alleviate the observed symptoms at home; it has been used by approximately 272,000 people since its launch. Semmelweis HELP can be used to check for acute symptoms. It is important to note that the app shows the degree of symptom match for specific illnesses; it does not provide a diagnosis. However, it is still more accurate and reliable than a random Internet search.

Translation: Dr. Balázs Csizmadia
Photo by Bálint Barta – Semmelweis University; cover photo/illustration: iStock/SbytovaMN