Коклюш

Инкубационный период: 5–21 день (чаще 7–10)

Катаральный период (1–2 недели): неотличим от обычного ОРВИ — насморк, лёгкий кашель, субфебрилитет. Максимальная контагиозность.

Спазматический (пароксизмальный) период (2–8 недель): приступы кашля (репризы): серия форсированных кашлевых толчков на выдохе → звучный инспираторный свист (реприз) → рвота после приступа. Лицо багровеет, вены шеи набухают. У грудных детей: апноэ БЕЗ репризов — самый опасный вариант.

Период обратного развития (2–6 недель): постепенное уменьшение частоты приступов. «Стодневный кашель».

Risk factors for pertussis infection and severe outcomes are primarily related to age, vaccination status, and proximity to infectious contacts.

Risk factors for infection:

• Waning immunity: Pertussis immunity is not lifelong, whether acquired through vaccination or natural infection. Acellular vaccine protection wanes after 4–6 years; whole-cell vaccine protection after 4–15 years; natural immunity after 7–20 years. This creates large pools of susceptible adolescents and adults who drive ongoing transmission.

• Household exposure: Secondary attack rates among susceptible household contacts are 80–90% — among the highest of any infectious disease. The primary source of infant infection is usually a household member (parent, sibling, or grandparent) with unrecognized pertussis.

• Incomplete vaccination: Children who have not completed the primary series (3 doses) have substantially higher risk. Even a partial series provides some protection, but full protection requires ≥3 doses.

• Crowded settings: Schools, daycare centers, military barracks, dormitories — pertussis outbreaks are frequently school-based.

• Epidemic cycles: Pertussis epidemics occur every 3–5 years even in countries with >90% DTP3 coverage, reflecting the accumulation of susceptible individuals as vaccine immunity wanes.

Risk factors for severe disease and death:

• Age <6 months: The highest-risk group for severe pertussis, hospitalization, and death. Infants this age have not yet completed the primary vaccine series and may lack protective maternal antibodies (especially if the mother was not vaccinated with Tdap during pregnancy). Apnea, pneumonia, pulmonary hypertension, and encephalopathy are disproportionately common.

• Prematurity and low birth weight: Increased risk of severe pertussis due to smaller airways, immature immune function, and lower transplacental antibody transfer.

• Absence of maternal Tdap vaccination: Infants born to unvaccinated mothers have 3–5× higher risk of pertussis in the first 2 months of life.

• Comorbid respiratory disease: Asthma, bronchopulmonary dysplasia, and other chronic lung conditions may exacerbate the severity and duration of pertussis.

• Extreme leukocytosis: WBC >100,000/µL in infants is an independent predictor of mortality, associated with leukostasis, pulmonary hypertension, and refractory hypoxemia.

Risk factors for prolonged cough in adults:

• Asthma and chronic respiratory conditions

• Active smoking

• Advanced age

• Immunocompromised status

• Апноэ: до 50–60% у грудных детей — основная причина смерти

• Пневмония: 5–10% (вторичная бактериальная — основная причина летальности)

• Энцефалопатия: 0,1–0,3% — судороги, кома

• Субконъюнктивальное кровоизлияние, переломы рёбер (от силы кашля)

• Грыжи (паховые, пупочные) от повышения внутрибрюшного давления

• Летальность: <0,01% в развитых странах, до 1–4% у новорождённых в развивающихся