Combatting Infant Pertussis with Cocooning

This approach seeks to reduce the risk of transmission by vaccinating all close contacts of vulnerable infants

In recent years, much controversy has been generated regarding the value of vaccinating children against communicable diseases. In the case of pertussis (also known as whooping cough), the call for vaccination across the lifespan receives support from the increasing incidence rates of the disease both in the United States and throughout the world.1,2 Within the U.S., the nadir of reported cases came in 1976 (1,010 cases), but has steadily increased since then.3 A substantial increase occurred in the mid-2000s when the incidence rate more than doubled between 2003 and 2004: 11,647 cases to 25,827 cases respectively.3

By 2012, the Centers for Disease Control and Prevention (CDC) reported 48,277 cases of pertussis in the U.S. —the highest number of new cases reported in one year since 1955.3 Twenty deaths were attributed to pertussis in 2012, and 16 of these deaths were infants less than one year old.4 Though incidence rates decreased from 2014 to 2015, the cyclical nature of pertussis infection with peaks every three to five years indicates that another resurgence is likely.4,5

The CDC and the Global Pertussis Initiative (GPI) recommend addressing this national, and indeed global, concern with an approach known as cocooning.6,7 This process involves reducing the risk of pertussis transmission by ensuring close contacts of vulnerable individuals are fully vaccinated against the disease.6

Pertussis: A Vaccine-Preventable Disease

The Bodetella pertussis bacteria is the most common cause of pertussis, a vaccine-preventable disease. This highly communicable respiratory infection is transmitted via aerosol droplets and initially presents with mild symptoms, including a low-grade fever and a cough associated with difficulty clearing secretions.4 In adults, the fever typically resolves within a week, but the cough may linger and worsen, devolving into the paroxysmal cough with inspiratory whoop for which the disease is known.4 Other symptoms may include post-tussive emesis and exhaustion.4

An At-Risk Population

Given the relatively innocuous initial symptoms, individuals may transmit the disease before realizing that they are infected. This infective process is particularly dangerous for infants (<1 year old), since they are too young to have received the full series of recommended vaccinations and experience more severe symptoms.6

The CDC recommends that pertussis vaccinations be part of the 5-dose DTaP series (diphtheria and tetanus toxoid, and acellular pertussis) given at 2, 4, and 6 months of age, again between 15-18 months and 4-6 years, with a Tdap (tetanus toxoid, diphtheria and acellular pertussis) booster between 11 and 18 years.8 Although partial protection results from even one DTaP dose, young infants remain at risk for infection and serious complications.6

Approximately half of all infants less than 12 months old who contract pertussis require hospitalization.7 Of those hospitalized, almost 25% develop secondary pneumonia (with an increased risk for refractory pulmonary hypertension), 67% experience significant apneic episodes, approximately 2% experience seizures, 1 in 300 develop encephalopathy, and 1% to 2% percent die.7

From 2012 to 2015, the CDC reported 51 pertussis-related deaths, 39 of which were infants less than a year old.4 In 2013, 12 of the 13 reported pertussis-related deaths that year were infants younger than three months.4


School-age children represent a common source of pertussis infection for younger siblings. However, unimmunized adults also serve as both a source of immediate pertussis infection, and as a reservoir for future infection.5 To reduce the risk of pertussis infection and its significant sequelae in infants less than one year old, the Global Pertussis Initiative (GPI) and the CDC recommend a strategy known as cocooning. Cocooning involves appropriate vaccination of all individuals coming in close contact with an infant less than 12 months old, including parents, siblings, extended family members, healthcare personnel and child-care providers.6,9,10

The first part of the cocooning strategy involves vaccinating mothers against pertussis during pregnancy, ideally between 27 and 36 weeks gestation.10 Administering the Tdap vaccine at this time permits the passive transfer of antibodies to the fetus, providing some degree of protection against pertussis in the neonate.6 If the Tdap vaccine is not administered during pregnancy, the mother should be vaccinated immediately postpartum. Additional Tdap vaccinations should be given during each future pregnancy.10

As noted above, the second part of cocooning calls for ensuring proper DTap/Tdap vaccination of all who are in close contact with infants less than one year old. Current childhood/adolescent immunization schedules provide sufficient coverage for individuals less than 19 years old.

However, since vaccine efficacy wanes over time, to ensure the best possible immunization status, adults should receive a one-time dose of Tdap if they have not previously received the vaccination after age 18.6 This identified group includes family members (both immediate and extended) as well as childcare and healthcare workers who serve this infant population.10

Unfortunately, a remarkably low number of adults maintain current Tdap immunizations in accordance with CDC recommendations. In 2013, only 17.2% of individuals 19 years or older had received the adult Tdap booster.11 Although this number represents an almost 3 percentage point increase from 2012, racial disparities continue to exist in adult Tdap uptake.11 White adults reported 19.7% coverage, while ethnic reporting showed Asian adults at 15.5%, Black adults at 12.6% and Hispanic adults at 10.2%. 11 Raising levels of awareness regarding the need for adult Tdap boosters is vital for the health of members of our communities across the lifespan.

What role do NPs and PAs play in combatting pertussis?

Support of cocooning presents an important advocacy opportunity for nurse practitioners (NPs) and physician assistants (PAs). While some patients and their families who interact with infants may realize the importance of Tdap vaccinations, others likely do not appreciate the risks.

Interventions are needed on the part of NPs and PAs, and can positively impact pertussis rates here in the United States. Given that healthcare provider recommendation remains the strongest indicator of Tdap booster uptake, NPs and PAs should regularly review and appropriately address immunization status at every visit, regardless of the patient’s age.12,13

Some additional advocacy suggestions include:

• Encourage parents to follow CDC-recommended vaccination schedules for their children.

• Encourage adult family members of young infants to receive their Tdap booster per CDC recommendations and educate them about the importance of cocooning.

• Assist parents with listing the names of all family members, friends and caregivers who will have contact with the new baby in its first year of life. Urge parents to promote a one-time Tdap vaccination among these identified individuals.

• Educate fellow healthcare providers and local community members (via community groups, school organizations and professional organizations) about cocooning and the value of receiving the one-time Tdap vaccination.

• Advocate for childcare employee vaccinations within your community, particularly Tdap vaccinations for individuals in contact with infants less than one year old.

• Advocate for cocooning on the legislative level, contacting local and state representatives to engender their support of appropriate legislation to protect young infants—one of our most vulnerable patient populations.

As providers, NPs and PAs are called to protect our most vulnerable populations, including young infants. NPs and PAs should leverage the contact and influence we have with families as well as individuals within our communities to encourage Tdap vaccination across the lifespan, per current CDC recommendations. In so doing, we will play a critical role in reducing the incidence of pertussis in the United States, especially in the very young.


1. Suryadevara M, Domachowske JB. Prevention of pertussis through adult vaccination. Hum Vaccin Immunother. 2015;11(7):1744-1747.

2. Chiappini E, StivalA, Galli L, de Martino M. Pertussis re-emergence in the post-vaccination era. BMC Infect Dis. 2013;13(1):1-12.

3. Pertussis cases by year (1922-2014). Centers for Disease Control and Prevention Web site.

4. Surveillance and reporting. Centers for Disease Control and Prevention Web site. Updated June 6, 2016. Accessed September 29, 2016.

5. Top K, Halperin S. Pertussis and Other Bordetella Infections. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J, eds. Harrison’s Principles of Internal Medicine. 19 ed. New York, NY: McGraw-Hill; 2015.

6. Forsyth K, Plotkin S, Tan T, von Konig C. Strategies to decrease pertussis transmission to infants. Pediatrics. 2015;135(6):e1475-e1482.

7. Pertussis (whooping cough). Centers for Disease Control and Prevention Web site.

8. Immunization schedules. Centers for Disease Control and Prevention Web site.

9. Guiso N, Liese J, Plotkin S. The Global Pertussis Initiative: Meeting report from the fourth regional roundtable meeting, France, April 14-15, 2010. Human Vaccines. 2010;7(4):481-488.

10. Sawyer M, Liang JL, Messonnier N, et al. Updated recommendations for use of tetanus toxoid, reduced diptheria toxoid, and acellular pertussis vaccine (Tdap) in pregnant women – Advisory Committee on Immunization Practices (ACIP), 2012. MMWR Morb Mortal Wkly Rep. 2013;62(07):131-135.

11. Williams WW, Peng-Jun L, O’Halloran A, et al. Vaccination coverage among adults, excluding influenza vaccination – United States, 2013. MMWR Morb Mortal Wkly Rep. 2015;64(04):95-102.

12. Hayles, E. H., Cooper, S. C., Wood, N., Sinn, J., & Skinner, S. R. (2014). What predicts postpartum pertussis booster vaccination? A controlled intervention trial. Vaccine;33(1):228-236.

13. Suryadevara M, Bonville CA, Cibula DA, et al. Pertussis vaccine for adults: Knowledge, attitudes, and vaccine receipt among adults with children in the household. Vaccine. 2014;32(51):7000-7004.

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