Postexposure Antimicrobial Prophylaxis

Key points

  • The primary objective of postexposure prophylaxis (PEP) is to prevent death and serious complications in people at high risk of severe pertussis infection.
  • Public health professionals can help identify those who need PEP.
  • Broader use of PEP may be reasonable in some settings.
Closeup of pharmacist holding pills in hand.

Use antibiotics only when necessary

Inappropriate use of antibiotics is an important consideration. CDC advises healthcare providers to prescribe and people to use antibiotics only when necessary. This can help reduce antibiotic resistance and protect against potential antibiotic side effects.

PEP use

CDC supports providing PEP especially to

  • Household contacts of a pertussis case
  • People at high risk of developing severe pertussis infection
  • Those who will have contact with people at high risk of developing severe pertussis infection

Household contacts

Timing of PEP‎

CDC supports providing PEP to all asymptomatic household contacts of a pertussis case within 21 days of onset of cough in the index patient.

Within families, studies demonstrate that secondary attack rates are high, even when household contacts are current with pertussis vaccinations.

Consideration can also be given to providing PEP to other contacts.

People at high risk

Timing of PEP‎

CDC supports providing PEP to people at high risk of severe infection within 21 days of exposure to an infectious pertussis case.

The following groups of people are at high risk of developing severe pertussis infection:

  • Infants under 12 months of age
  • People with pre-existing health conditions that may be exacerbated by a pertussis infection

Infants: Severe and sometimes fatal pertussis-related complications occur in infants under 12 months of age. This especially occurs among infants under 4 months of age.

People with pre-existing health conditions that may be exacerbated by pertussis: These people include, but are not limited to, people with immunocompromising conditions or moderate to severe medically treated asthma.

Those who will have contact with people at high risk

Timing of PEP‎

CDC supports providing PEP to people in contact with those at high risk of severe infection within 21 days of exposure to an infectious pertussis case.

Those who will have contact with people at high risk of developing severe pertussis infection include:

  • Pregnant women in their third trimester
  • All people in high-risk settings

Pregnant women in third trimester: Women in their third trimester of pregnancy may be a source of pertussis to their newborn infant.

All people in high-risk settings: This is focused in particular on settings that include infants under 12 months of age or women in their third trimester of pregnancy.

These settings include:

  • Neonatal intensive care units
  • Childcare settings
  • Maternity wards

Broader use of PEP in some settings

A broader use of PEP may be appropriate in limited closed settings when

  • The number of identified cases is small and
  • There isn't a community-wide outbreak.

However, when continued transmission of pertussis is evident, multiple rounds of antibiotics wouldn't be recommended.

Instead, healthcare providers should monitor people exposed to pertussis for onset of pertussis signs and symptoms for 21 days.

During increased incidence and widespread community transmission

Extensive contact tracing and widespread 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. However, there are no data to suggest widespread PEP use among contacts effectively controls or limits outbreaks.