Doctors are urging parents to stay vigilant this winter as whooping cough cases may rise. Often referred to as the “winter killer,” this highly contagious bacterial infection can trigger severe coughing fits, breathing difficulties, and the characteristic “whooping” sound. Infants and young children are particularly vulnerable, facing serious complications such as pneumonia and, in severe cases, brain damage.

The Indian Meteorological Department (IMD) has issued a severe weather alert for the approaching winter season, warning that La Niña conditions could lead to plunging temperatures, heavy snowstorms, and erratic weather across the country. With a 71% likelihood of La Niña developing between October and December 2025, experts are anticipating an unusually harsh winter. ¹

Pertussis, commonly known as whooping cough, is caused by the bacterium Bordetella pertussis, a gram-negative organism that spreads through respiratory droplets or aerosols when an infected person coughs or sneezes. It is a highly contagious infection that can cause severe coughing fits and breathing difficulties. Infants and young children are particularly vulnerable, with complications ranging from pneumonia to brain injury. The disease gets its nickname from the distinctive “whooping” sound that follows intense coughing episodes.

The illness typically progresses through three stages:

• The catarrhal stage, marked by mild cold-like symptoms such as runny nose, mild fever, and cough.

• The paroxysmal stage, characterized by repeated bouts of violent coughing, often followed by a gasping “whoop” as the person struggles to inhale. These coughing fits, also known as paroxysms, may lead to vomiting, exhaustion, or difficulty breathing.

• The convalescent stage, during which symptoms gradually improve over several weeks.

The disease can last from six to ten weeks, sometimes earning it the nickname “the 100-day cough.”

Transmission occurs easily through respiratory droplets, making outbreaks difficult to control in community settings. Health experts emphasize the importance of timely vaccination for both children and adults, as immunization remains the most effective preventive measure.²

A recent study from Zhejiang Province, China, highlights a notable resurgence of pertussis (whooping cough) following the COVID-19 pandemic. Researchers analyzing over 8,500 patients with acute respiratory infections found that children and adolescents, particularly those around 10 years old, were most affected, with pertussis positivity peaking at 31.5% in early 2024.

The study also showed higher infection rates in outpatients and patients with lower respiratory tract infections. Experts attribute this rise to reduced public health vigilance and the easing of pandemic-era precautions, emphasizing the critical need for timely vaccination and strengthened preventive measures to protect vulnerable populations, especially children. ³

In the initial stage, pertussis symptoms typically persist for one to two weeks and are often mild. Common early signs include a runny or congested nose, a low-grade fever (below 100.4°F), and an occasional, mild cough.

In infants, whooping cough can present differently than in older children. Many babies may not exhibit the characteristic cough at all. Instead, they can experience apnea, which are dangerous pauses in breathing. This may lead to cyanosis, causing the skin to turn blue, or noticeable breathing difficulties. ²

One to two weeks after initial symptoms, individuals with pertussis may develop intense coughing episodes called paroxysms. These fits can last from one to six weeks, and in some cases up to ten weeks, often worsening as the illness progresses. During coughing fits, affected individuals may:

• Produce a high-pitched “whoop” when inhaling after a fit

• Vomit during or immediately after coughing

• Experience extreme fatigue, though they may appear well between episodes

• Have trouble sleeping at night

• Struggle to breathe

• In rare cases, suffer a rib fracture due to the force of coughing

In adults, persistent coughing can sometimes lead to fainting (syncope), insomnia, and even weight loss due to the physical toll of repeated episodes. Many patients describe these episodes as the most severe cough they have ever experienced.²

Approximately one in three infants under the age of one who contract whooping cough require hospitalization, with younger babies being at higher risk for severe illness. Among hospitalized infants, complications can be serious:

• Apnea, or dangerous pauses in breathing: 68%

• Pneumonia, or lung infection: 22%

• Convulsions, involving violent, uncontrolled shaking: 2%

• Encephalopathy, or brain disease: 0.6%

• Death due to complications: 1%

Early treatment of whooping cough is crucial, ideally before severe coughing fits develop. The antibiotic erythromycin is commonly used as the treatment of choice, which helps reduce the severity of symptoms and limits the spread of infection.

Recovery from whooping cough is often gradual, with coughing fits becoming milder and less frequent over time. In some cases, the cough may temporarily subside but can return during other respiratory infections. These episodes may reappear several months after the initial illness began.²

Whooping cough is preventable with the DTaP vaccine (Diphtheria, Tetanus, and acellular Pertussis), where the “P” component protects against pertussis. Children are recommended to receive five doses—at 2 months, 4 months, 6 months, 15–18 months, and again at 4–6 years.

Older children should receive a booster dose (Tdap) around 10–12 years of age to maintain protection. Adults who frequently interact with infants, such as parents, grandparents, and healthcare workers, are also advised to get vaccinated. Pregnant women should receive a dose during the third trimester to help pass on protective antibodies to the newborn.

However, experts caution that immunity from the vaccine or previous infection can wane over time, which is one reason for the resurgence of pertussis cases globally. Maintaining booster coverage is essential for continued protection.

References

1. India Meteorological Department. Current Weather Status and Extended Range Forecast for the Next Two Weeks (11–24 September 2025). Press Release, 11 September 2025. Earth System Science Organization, Ministry of Earth Sciences, Government of India. https://mausam.imd.gov.in/Forecast/marquee_data/ERF%2011.09.25.pdf.

2. Centers for Disease Control and Prevention. About Whooping Cough. Last modified April 2, 2024. https://www.cdc.gov/pertussis/about/index.html.

3. Wang, H. "Post-COVID-19 Pandemic Changes in Pertussis Incidence in Zhejiang Province, China." Frontiers in Public Health 12 (2024): Article 11342075. https://pmc.ncbi.nlm.nih.gov/articles/PMC11342075/.

Reviewed by Dr. Munish Kumar Raizada, MD, FAAP

(Rh/Eth/ARC/MSM)