Pertussis: Trends, Prevention and Challenges · 11/12/2014 5 Page 25 xxx00.#####.ppt 11/12/2014 2:57:46 PM Pediatrics Response to booster vaccination is robust to all pertussis antibodies

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Pediatrics

Pertussis:

Trends, Prevention

and Challenges

Flor M. Munoz, MD

Associate Professor

Pediatric Infectious Diseases

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Disclosure

I do not have any relevant conflicts of

interest to disclose.

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Objectives

1. Epidemiology of Pertussis in US and Texas

2. Current Pertussis Prevention Strategies and

Vaccine Coverage

3. Update on Disease Prevention Strategies:

Maternal Immunization

4. Challenges and Future Direction of Pertussis

Prevention in the US

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Pertussis “Whooping cough”

• Starts with a mild URI without fever (Catarrhal stage), then Paroxysmal Cough, Whoop, Post-Tussive Emesis for >2-3 weeks.

• Affects infants, children, adolescents, adults

• ~48.5 million cases per year worldwide

• ~ 295,000 deaths

• Infants < 6 mo have the highest attack rate, morbidity and mortality. Diagnosis often delayed.

• Children, adolescents and adults: Often misdiagnosed. Up to 20% of prolonged coughing illnesses in adults are due to pertussis. Reservoirs. Complications.

Source: CA Dept.of Health website

Parents 55%

Siblings 16%

Aunts &

Uncles 10%

Friends &

Cousins 10%

Grandparents 6% Caretakers 2%

Wendelboe, A, et al PIDJ. 2007;26:293-99.

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~49,000 cases

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Pertussis in U.S. 2014

• 20,284 cases nationwide

(as of 09/20/14)

Reported in 50 states and

Washington, D.C.

30% increase from same time

last year

• California has declared an

epidemic

Over 8,000 cases (as of 9/15/14)

3.5% of cases have required

hospitalization

One death (5 week old)

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Source: CDC.gov

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2009 2009

2005

2013

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Pertussis in Texas

• DSHS reported 3,986 pertussis cases in 2013.

• The annual total surpassed the recent high of 3,358 cases in 2009.

• There were 5 pertussis-related deaths in 2013; All infants too young to be vaccinated and none of the mothers were vaccinated with Tdap during pregnancy.

• From 2000-2013, a total of 48 deaths were attributed to pertussis

• In 2014, 2,045 cases have been reported as of Nov 3, 2014; 2 deaths (< 3 months, unvaccinated mother; teen with co-morbidities); and a 11% hospitalization rate (80% < 1 year old)

http://www.dshs.state.tx.us/idcu/disease/pertussis/

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Pertussis Prevention Strategies - ACIP

• DTaP 2,4,6 mo + 12-18 mo and 4-6 yr

• Tdap Adolescents 11-12 yr and catch up 13-18 yr

• Tdap Adults 18-64 yr

• Health care workers

• Tdap not Td for tetanus post-exposure prophylaxis

MMWR 2011-13

1997

2005

2006

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MMWR 2011-13

Pertussis Prevention Strategies - ACIP

• Post-partum women and close contacts of infants

(cocoon strategy)

•Breastfeeding NOT a contraindication

• Pregnant women 2nd-3rd trimest. if no previous Tdap

• Use Tdap without concern for interval since last TT

• People > 65 yrs in contact with infants

• Pregnant women 27-36 wks gest EVERY pregnancy

2008

2011

2012

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Resurgence despite “high” vaccine coverage

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Tdap Effectiveness wanes within 3-4 years

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Antibodies post Tdap Rapidly decline in first 1-2 years Slower decline over 5-10 years Close to pre-vaccination at 10 years Note: No defined level of antibody correlates absolutely with protection! Increase in disease after ~5 years correlates with decrease in antibody concentrations

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Response to booster vaccination is robust to all pertussis antibodies after 5 or 10 years Data available for a second dose only, not subsequent doses (ie. decennial Tdap)

Tdap Effectiveness and Revaccination

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Infant DTaP Effectiveness and

Duration of Protection

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Pertussis Hospitalizations in Infants and Vaccine Coverage

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Waning protection after 5th dose of DTaP

Protection from the 5th dose of DTaP wanes substantially during the 5 years after vaccination in children who received only DTaP Risk of pertussis increased by an average of 42% per year after vaccination Vaccine effectiveness decreases over time and duration of protection depends on initial effectiveness

Klein NP. Et al NEJM 2012;367:1042-9

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Comparative Effectiveness of Acellular vs.

Whole-Cell Pertussis Vaccines in Teenagers

Klein NP, et al Pediatrics 2013;131:e1716–e1722

Increasing number of DTaP doses from 0 to 4 was significantly associated with increasing % of positive PCR

Risk of pertussis: 4DTaP vs 4DTwP OR 5.63 Mixed vs 4DTwP OR 3.77

If no Tdap booster: 4DTaP vs 4DTwP OR 9.92

With Tdap booster: 4DTaP vs 4 DTwP OR 4.85

* Those given whole-cell pertussis vaccines in childhood were more protected than those given acellular pertussis vaccines

* Tdap booster remains best means currently available to protect teens

Percentage of pertussis PCR tests with a positive result in the study population by pertussis vaccine type for the first 4 doses received between 1 and 24 months of age, Jan 2010 to Dec 2011.

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Summary:

Immune responses to Pertussis vaccines

• DTaP and Tdap yield high specific antibody titers after imm

• Whole cell and acelllular vaccines elicit different priming

response:

DTwP (and natural infection) produce Th1 cytokine response

DTaP elicit mixed Th1/Th2 responses, skewed toward Th2, at

6 months and probably until the 5th dose

• Immunity and protection wane faster than anticipated (3-5 y)

•Data not supportive for change in schedule (more doses) in

adults (HCP)

Ausiello CM et al. Infect Immun 1997;65(6):2188; Mascart F et al. Vaccine 2007;25(2):391 Ryan M et al. Immunology 1998;93(1):1-10; Ausiello CM et al. Infect Immun 1999;67(8):4064 Dirix V et al. Vaccine 2009;27(43):6042; Hendrikx LK et al.Vaccine 2011;29(40):6874

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Current Pertussis Prevention Strategies

• “On time and on schedule vaccination”

• Improve coverage in adults, including HCP

• Maternal Immunization

‐Recommended since 2012 – coverage remains low ~16-18%

in US

‐Recommended in UK, Australia, other countries based on

epidemiology

‐Most direct and effective method to protect infants against

pertussis

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Maternal Immunization with Tdap Study

• Maternal immunization with Tdap* is safe and will boost maternal antibodies to pertussis antigens, which can be efficiently transferred transplacentally

• Infants born to mothers vaccinated during pregnancy will have higher concentrations of pertussis specific antibodies that could protect them during the first 2 months of life, a period of vulnerability, high morbidity and mortality

• Maternal immunization with Tdap should NOT interfere with infant responses to primary and booster vaccination with DTaP**

*Adacel® (SP) contains PT (2.5 ug), FHA (5 ug), PRN (3 ug), FIM 1-2 (5 ug), DT (2LfU) and TT (5LfU)

**Pentace®l (SP) contains PT, FHA, PRN, FIM1, FIM2, Tetanus and Diphtheria Toxoids / Hib / IPV

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Maternal Immunization with Tdap

Study Design

Arm Group N=

Single dose administered to pregnant women

with crossover design

Antepartum Postpartum

Intervention 1 32 Tdap Saline

Control 2 16 Saline A

Single dose administered to non-pregnant women

Control 3 32

Tdap vaccine

Tdap

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Munoz FM et al. JAMA May 7, 2014 Page 36


Safety: Proportion of Subjects with ANY Injection Site or Systemic Reaction by Day and Study Group

Saline

Saline

Injection Site Reactions Systemic Reactions

Saline

Saline

Antepartum dose Antepartum dose Postpartum dose Postpartum dose

Tdap

Tdap

Tdap

Tdap

Tdap

Tdap

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Safety Outcomes

V. Antepartum (N-33) V. Post-Partum (N-15)

C-section delivery 9 (27.27%) 9 (60%)

Infant Preterm Del (<37 wk) 3 (9.1%) 1 (6.7%)

Infant AGA SGA

27 (84.4%) 1 (3.1%)

13 (86.7%) 0

Infant Weight Mean (SD) Median

3.2 Kg (0.5) 3.2 Kg

3.5 Kg (0.7) 3.3 Kg

Infant APGAR scores (Median at 1/5 minutes)

8 / 9 8 / 9

No significant differences in infant exam findings and neonatal course, growth and development, and Bailey developmental exam No documented cases of pertussis in mothers or infants No deaths, no vaccine-related SAEs

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Transplacental Antibody Transfer

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Immunogenicity (GMC) Pertussis Antibodies in

Mothers and Infants

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Tdap Safety in Pregnancy

• Donegan K, et al, UK

• Observational cohort study

• UK Clinical Practice Research Datalink

• Pop: 20,074 pregnant women with a median age of 30 yr who received Tdap-IPV (SP) in the 3rd trimester (28-38 wk) since October 2012 and a matched historical unvaccinated control group

• Primary Outcome: Adverse events identified from clinical diagnoses during pregnancy with additional data from the matched child record identified through mother-child linkage.

• The primary event of interest was stillbirth (Def: intrauterine death after 24 weeks’ gestation).

Donegan K, et al. BMJ 2014;349:g4219 Page 46


Tdap Safety in Pregnancy

•There was no increased risk of stillbirth in the 14 days after vaccination

(incidence rate ratio 0.69, 95% CI 0.23 to 1.62) or later in pregnancy (0.85,

0.44 to 1.61) compared with historical national rates.

•There was no evidence that vaccination accelerated the time to delivery

(hazard ratio 1.00 0.97 to 1.02)

•There was no evidence of an increased risk of stillbirth, maternal or

neonatal death, pre-eclampsia or eclampsia, hemorrhage, fetal

distress, uterine rupture, placenta or vasa praevia, Cesarean delivery,

low birth weight, or neonatal renal failure, all serious events that can

occur naturally in pregnancy. Congenital anomalies not sought (registries).

•UK Yellow Card – no increase in pregnancy complications

Donegan K, et al. BMJ 2014;349:g4219

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US – VSD Coverage and Safety of Tdap during

pregnancy (Kharbanda et al. 2014)

• Coverage during pregnancy ~ 15-18% 2007-2012

• Safety cohort study 2010-12, observational

• Outcomes:

• Hypertensive disorders, Chorioamnionitis

• Preterm delivery (<37 wk), SGA (< 10%)

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Maternal Vaccination Prevents Leukocytosis, not Colonization

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Summary

•Childhood and adolescent Pertussis disease has increased despite high DTaP and Tdap coverage and effective vaccines (vaccines do protect!)

•Pertussis epidemiology changed since switch to less reactogenic acellular pertussis vaccines

•Factors involved: Rapidely waning immunity, awareness and improved diagnostic methods, unvaccinated groups, incomplete reservoir elimination (adults, close contacts, HCW), changes in pathogen?

•Potential Solutions:

‐Short term: Maternal immunization to protect most vulnerable infants, Tdap vaccination of adolescents and adults; Improved coverage and On Time vaccination

‐Long term: Need new pertussis vaccines!

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Documents

Pertussis: Trends, Prevention and Challenges · 11/12/2014 5 Page 25 xxx00.#####.ppt 11/12/2014 2:57:46 PM Pediatrics Response to booster vaccination is robust to all pertussis antibodies