Whooping cough

Whooping cough
Other names	Pertussis, 100-day cough
A young boy coughing due to pertussis.
Specialty	Infectious disease
Symptoms	Runny nose, fever, cough[1]
Complications	Vomiting, broken ribs, exhaustion[1][2]
Duration	~ 3 months[3]
Causes	Bordetella pertussis (spread through the air)[4]
Diagnostic method	Nasopharyngeal swab[5]
Prevention	Pertussis vaccine[6]
Treatment	Antibiotics (if started early)[7]
Frequency	16.3 million (2015)[8]
Deaths	58,700 (2015)[9]

Whooping cough (/ˈhuːpɪŋ/), also known as pertussis or the 100-day cough, is a highly contagious, vaccine-preventable bacterial disease.^[1][10] Initial symptoms are usually similar to those of the common cold with a runny nose, fever, and mild cough, but these are followed by two or three months of severe coughing fits.^[1] Following a fit of coughing, a high-pitched whoop sound or gasp may occur as the person breathes in.^[1] The violent coughing may last for 10 or more weeks, hence the phrase "100-day cough".^[3] The cough may be so hard that it causes vomiting, rib fractures, and fatigue.^[1][2] Children less than one year old may have little or no cough and instead have periods where they cannot breathe.^[1] The incubation period is usually seven to ten days.^[11] Disease may occur in those who have been vaccinated, but symptoms are typically milder.^[1]

Pertussis is caused by the bacterium Bordetella pertussis, which is spread easily through the coughs and sneezes of an infected person.^[4][12] People are infectious from the start of symptoms until about three weeks into the coughing fits.^[7] Diagnosis is by collecting a sample from the back of the nose and throat.^[5] This sample can then be tested either by culture or by polymerase chain reaction.^[5]

Prevention is mainly by vaccination with the pertussis vaccine.^[6] Initial immunization is recommended between six and eight weeks of age, with four doses to be given in the first two years of life.^[13] Protection from pertussis decreases over time, so additional doses of vaccine are often recommended for older children and adults.^[14] Vaccination during pregnancy is highly effective at protecting the infant from pertussis during their vulnerable early months of life, and is recommended in many countries.^[15] Antibiotics may be used to prevent the disease in those who have been exposed and are at risk of severe disease.^[16] In those with the disease, antibiotics are useful if started within three weeks of the initial symptoms, but otherwise have little effect in most people.^[7] In pregnant women and children less than one year old, antibiotics are recommended within six weeks of symptom onset.^[7] Antibiotics used include erythromycin, azithromycin, clarithromycin, or trimethoprim/sulfamethoxazole.^[7] Evidence to support interventions for the cough, other than antibiotics, is poor.^[17] About 50% of infected children less than a year old require hospitalization and nearly 0.5% (1 in 200) die.^[1][2]

An estimated 16.3 million people worldwide were infected in 2015.^[8] Most cases occur in the developing world, and people of all ages may be affected.^[6][17] In 2015, pertussis resulted in 58,700 deaths – down from 138,000 deaths in 1990.^[9][18] Outbreaks of the disease were first described in the 16th century.^[11] The bacterium that causes the infection was discovered in 1906.^[11] The pertussis vaccine became available in the 1940s.^[11]