Rising Risks of Respiratory Infections During Seasonal Transitions: Be Alert to the Threat of a “Quaddemic”

As the seasons change, health experts are warning of a potential resurgence of COVID-19, raising concerns over a “Quaddemic”—the simultaneous circulation of four respiratory viruses: COVID-19, seasonal flu, RSV, and HMPV.

Sudden temperature fluctuations during transitional weather significantly increase the spread of respiratory infections, especially among infants, young children, and adolescents under 18. Learn how to protect your family with practical tips and up-to-date information from H PLUS International Medical Center.

The current state of respiratory infections in Vietnam

In Vietnam, the incidence of respiratory infections varies by season and age group, with children under five being the most vulnerable. On average, children in this group may experience 4 to 6 respiratory infections per year, with a marked increase during season changes.

As of October 2024, respiratory infection data in Vietnam include:

• Children’s Hospital 1 (Ho Chi Minh City): As of October 6, 2024, 4,693 cases of bronchiolitis were recorded (a 29% increase from the same period in 2023), and 8,176 cases of pneumonia (a 9.2% decrease). From 2019 to 2024, annual figures remained stable with approximately 5,000 bronchiolitis cases and 10,000 pneumonia cases per year.

• Ho Chi Minh City: The disease surveillance system recorded 16,000–18,000 respiratory infections per month in 2024.

For 2025, no official statistics have been released yet, but according to the World Health Organization (WHO), countries in the Northern Hemisphere are experiencing a seasonal rise in acute respiratory infections, driven by influenza, RSV, and other common viruses such as HMPV.

Additionally, RSV has recently spread to China and other countries, along with increasing cases of human metapneumovirus (HMPV).

Dr. Yang Moo-yeol, a pediatric and adolescent medicine specialist at H PLUS Yangji Hospital, emphasized:
“Respiratory infections, if not treated in time, can lead to serious complications, especially in young children. They are often overlooked because symptoms resemble the common cold. For infants and toddlers, prompt treatment at the first sign of respiratory issues is essential.”

Overview of three common respiratory infections

Influenza

Influenza is an acute respiratory illness caused by flu viruses, mainly influenza A and B strains.

Symptoms typically include sore throat, muscle aches, headache, high fever, cough, phlegm, and runny nose—easily mistaken for a cold. In children, additional symptoms like vomiting and diarrhea may occur.

While systemic symptoms usually subside within 3–4 days, cough and sore throat can linger even after the fever resolves, sometimes lasting several more days.

Respiratory Syncytial Virus (RSV)

RSV is a virus that causes acute respiratory infections with symptoms similar to a cold. It is the leading cause of bronchiolitis and pneumonia in children under one year old.

Most children contract RSV within their first two years of life, with about 20–30% developing complications such as bronchiolitis or pneumonia. RSV is also the most common cause of respiratory-related hospitalizations in children, especially in the fall and winter.

Common symptoms include runny nose, cough, fever, difficulty feeding, rapid breathing, and wheezing.

Human Metapneumovirus (HMPV)

HMPV is a globally circulating respiratory virus currently rising in China and several other countries. It causes acute respiratory infections, particularly in infants and young children aged 0 to 6.

Symptoms resemble those of the flu or common cold, including fever, cough, phlegm, nasal congestion, and runny nose. Severe cases may progress to bronchiolitis or pneumonia, posing significant health risks for young children.

How to prevent respiratory infections

Respiratory infections are highly contagious, so minimizing contact with others when symptoms appear is essential.

For influenza and COVID-19, vaccination remains an effective preventive measure. This season’s flu vaccine closely matches circulating strains, offering strong protection.

Currently, there are no specific treatments for RSV and HMPV. Symptoms often resolve on their own within 1–2 weeks, but these viruses can be serious for infants and toddlers. Parents should monitor their child’s condition closely, especially for signs of dehydration. Ensuring proper hydration, rest, antipyretics, and IV fluids when needed can support recovery.

Dr. Yang Moo-yeol noted:
“Vaccination plays a vital role in preventing infections and reducing complications and mortality. Since RSV and HMPV spread through contact with infected body fluids, limiting exposure to infected individuals is a key preventive strategy.”

Comprehensive respiratory care and vaccination at H PLUS International Medical Center

H PLUS offers a complete respiratory care package developed by experienced specialists from leading hospitals. We are equipped with state-of-the-art facilities including X-ray, 128-slice CT scanners, and pulmonary function testing to ensure accurate diagnosis and effective treatment.

We also provide vaccinations against common respiratory illnesses such as seasonal flu, pneumonia, bronchitis, COVID-19, and RSV. With high-quality vaccines, safe immunization procedures, and a dedicated medical team, we are committed to delivering the best protection for you and your family.

At H PLUS, we combine a modern, elegant environment with personalized care, ensuring your health is in good hands.

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Phòng khám Đa khoa Quốc tế H PLUS | H PLUS International Medical Center
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