Postexposure Antimicrobial Prophylaxis

Information for public health professionals

The primary objective of postexposure antimicrobial prophylaxis (PEP) should be to prevent death and serious complications from pertussis in people at increased risk of severe disease.

During increased incidence and widespread community transmission

Extensive contact tracing and broad scale use of PEP among contacts may not be an effective use of limited public health resources. Antibiotics may prevent pertussis if given prior to symptom onset, but there are no data to indicate that widespread use of PEP among contacts effectively controls or limits the scope of pertussis outbreaks.

Target postexposure antibiotics to people at high risk

Another important consideration is the overuse of antibiotics. CDC advises healthcare professionals and parents to use antibiotics only when necessary to further reduce antibiotic resistance and protect against potential side effects from antibiotics. Given these considerations, CDC supports targeting postexposure antibiotic use to people at high risk of developing severe pertussis, as well as people who will have close contact with others at high risk of developing severe pertussis. Many state health departments have implemented similar approaches.

CDC supports providing PEP to:

  • All household contacts of a pertussis case. Within families, studies demonstrated that secondary attack rates are high, even when household contacts are current with pertussis immunizations. Administration of antimicrobial prophylaxis to asymptomatic household contacts within 21 days of onset of cough in the index patient can prevent symptomatic infection.
  • High risk people within 21 days of exposure to an infectious pertussis case. High risk people are those who personally are at high risk of developing severe illness, or those people who will have close contact with people at high risk of severe illness. High risk people include
    • Infants and women in their third trimester of pregnancy. Severe and sometimes fatal pertussis-related complications occur in infants under 12 months of age, especially among infants under 4 months of age. Women in their third trimester of pregnancy may be a source of pertussis to their newborn infant.
    • All people with pre-existing health conditions that may be exacerbated by a pertussis infection. These people include, but are not limited to, immunocompromised people and those with moderate to severe medically treated asthma.
    • People who have close contact with people who are at high risk. These people include infants under 12 months of age, pregnant women or people with pre-existing health conditions at risk of severe illness or complications.
    • All people in high risk settings that include infants under 12 months of age or women in the third trimester of pregnancy. These settings include, but are not limited to, neonatal intensive care units, childcare settings, and maternity wards.

Use in closed settings with small case counts

A broader use of PEP may be appropriate in limited closed settings when the number of identified cases is small and when a community-wide outbreak is not ongoing. However, when continued transmission of pertussis is evident, multiple rounds of antibiotics would not be recommended. Rather than repeating a course of antibiotics, health professionals should monitor people exposed to pertussis for onset of pertussis signs and symptoms for 21 days.

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