Postexposure Antimicrobial Prophylaxis

Information for Health Professionals

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

There is increasing incidence and widespread community transmission of pertussis. 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 disease 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.

Another important consideration is the overuse of antibiotics. CDC is engaged in actively promoting the judicious use of antibiotics among healthcare providers and parents. 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. In response to the growing number of pertussis cases, many state health departments have already implemented similar approaches.

Accordingly, CDC supports the following:

  • 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.
  • Providing PEP to 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 aged <12 months, especially among infants aged <4 months. 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 (for example, but not limited to, immunocompromised people and those with moderate to severe medically treated asthma).
    • People who themselves have close contact with either infants under 12 months, pregnant women or individuals with pre-existing health conditions at risk of severe illness or complications.
    • All people in high risk settings that include infants aged <12 months or women in the third trimester of pregnancy. These include, but are not limited to neonatal intensive care units, childcare settings, and maternity wards.
  • 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, you should monitor people exposed to pertussis for onset of pertussis signs and symptoms for 21 days.


  1. Letter of Guidance for Parents and Clinicians during Outbreaks
  2. Be Antibiotics Aware Website
  3. Sprauer MA, Cochi SL, Zell ER, et al. Prevention of secondary transmission of pertussis in households with early use of erythromycin. Am J Dis Child.1992;146(2):177–81.
  4. Dodhia H, Miller E. Review of the evidence for the use of erythromycin in the management of persons exposed to pertussis. Epidemiol Infect.1998;120(2):143–9.
  5. Halperin SA, Bortolussi R, Langley JM, Eastwood BJ, De Serres G. A randomized, placebo-controlled trial of erythromycin estolate chemoprophylaxis for household contacts of children with culture-positive Bordetella pertussis infection. Pediatrics. 1999;104(4):e42.
  6. von König CH. Use of antibiotics in the prevention and treatment of pertussis. Pediatr Infect Dis J. 2005;24(5 Suppl):S66–8.
  7. Alexander EM, Travis S, Booms C, et al. Pertussis outbreak on a neonatal unit: identification of a healthcare worker as the likely source. J Hosp Infect. 2008;69(2):131–4.
  8. Elumogo TN, Booth D, Enoch DA, et al. Bordetella pertussis in a neonatal intensive care unit: identification of the mother as the likely source. J Hosp Infect. 2012;82(2):133–5.
  9. CDC. Recommended antimicrobial agents for the treatment and postexposure prophylaxis of pertussis: 2005 CDC Guidelines. MMWR. 2005;54(RR14):1-16.
  10. Clark TA. Responding to pertussis. J Pediatr. 2012;161(6):980–2.

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Page last reviewed: November 18, 2019