What is the risk of respiratory complications in an unvaccinated child presenting with a cough?

From the Guidelines

Risk of Respiratory Complications in Unvaccinated Children with Cough

The risk of respiratory complications in an unvaccinated child presenting with a cough is high, particularly for severe and life-threatening complications such as pneumonia, seizures, encephalopathy, and death 1.

Key Factors Influencing Risk

• Age: Unvaccinated or incompletely vaccinated infants aged <12 months have the highest risk for severe and life-threatening complications and death 1.
• Vaccination Status: Unvaccinated children are at a higher risk of developing pertussis and its complications compared to vaccinated children, with a median duration of cough being 52 to 61 days in unvaccinated children aged < 6 years 1.
• Infectious Agent: Pertussis (Bordetella pertussis) is a common cause of chronic cough in children, with a high secondary attack rate exceeding 80% among susceptible persons 1.

Respiratory Complications

• Pneumonia: A significant complication of pertussis, with 22% of patients less than 1 year of age reported to have pneumonia 1.
• Seizures and Encephalopathy: Also reported as complications, although less frequently than pneumonia 1.
• Death: A potential outcome, particularly in young infants, with 0.6% of patients less than 1 year of age reported to have died from pertussis 1.

Prevention and Management

• Vaccination: Completion of a primary series of DTP vaccine early in life is essential to prevent pertussis and its complications 1.
• Antimicrobial Agents: Recommended for the treatment and postexposure prophylaxis of pertussis, particularly in high-risk individuals such as unvaccinated infants 1.

From the Research

Risk of Respiratory Complications in Unvaccinated Children

The risk of respiratory complications in an unvaccinated child presenting with a cough is significant, as evidenced by several studies 2, 3, 4, 5, 6.

• Unvaccinated infants are at a higher risk of developing severe pertussis, which can lead to respiratory failure, pulmonary hypertension, and even death 2, 3.
• The clinical presentation of pertussis in unvaccinated infants can be severe, with symptoms such as paroxysmal cough, inspiratory whoop, cyanosis, apnea, and suffocation 3.
• The length of stay in the hospital for unvaccinated infants with pertussis is significantly longer than for vaccinated infants, and the risk of complications such as severe pneumonia, pulmonary consolidation, and encephalopathy is higher 3.
• Leukocytosis is common in pertussis cases, and the white blood cell count is higher in unvaccinated infants and those with severe disease 3.
• The risk factors for severe pertussis include a history of exposure, fever, leukocytosis, and pulmonary consolidation or atelectasis on chest imaging 3.

Severity of Pertussis in Unvaccinated Infants

The severity of pertussis in unvaccinated infants can be life-threatening, with a high mortality rate 3, 4.

• Infants less than 3 months old who are unvaccinated are at the highest risk of developing severe pertussis and experiencing severe complications 3.
• The cumulative incidence of pertussis in unvaccinated preschool cohorts can be high, with estimates ranging from 31% to 54% 6.
• The diagnosis of pertussis in unvaccinated infants can be challenging, and the disease may be underreported due to the lack of specific symptoms and the limitations of surveillance systems 6.

Importance of Vaccination

Vaccination is crucial in preventing pertussis and reducing the risk of respiratory complications in infants and children 4, 5.

• Acellular pertussis vaccines have been shown to be effective in preventing pertussis, but the emergence of pertactin-deficient clinical isolates may impact the efficacy of these vaccines 5.
• Vaccination strategies should be implemented to prevent the transmission of B. pertussis and the occurrence of severe and fatal pertussis in young infants 2, 4.