Vaccine-Preventable Diseases 1 2/16/15 I have nothing to disclose - - PDF document
2/16/15 Emerging Issues in Pediatric Infections (focus on Vaccine Preventable Diseases) C A R O L G L A S E R , D V M , M P V M , M D PEDIATRIC INFECTIOUS DISEASES KAISER PERMANENTE OAKLAND & DEPARTMENT OF PEDIATRICS DIVISION OF
◆ 2/16/15 ◆ 1
C A R O L G L A S E R , D V M , M P V M , M D
PEDIATRIC INFECTIOUS DISEASES KAISER PERMANENTE OAKLAND & DEPARTMENT OF PEDIATRICS DIVISION OF PEDIATRIC INFECTIOUS DISEASES UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
with an emphasis on
◆ 2/16/15 ◆ 2
Resurgence of VPDs due to failure to immunize and
Measles No indigenous transmission in the U.S., but continued
transmission in many parts of the world, including Europe, means it’s still an issue in the U.S.
The Pertussis Problem Why has the incidence been increasing in the U.S.? Mumps Why are there still cases in the U.S. even though immunization
rates are high?
Other vaccine-preventable diseases
◆ 2/16/15 ◆ 3
Childhood vaccination rates plummeted in Europe
Although results of the 1998 study have been shown
In some parts of Europe, MMR
◆ 2/16/15 ◆ 4
6/28: Onset of fever 6/29 runny nose 7/2 rash around mouth 7/3 erythematous mp rash spread from face to whole
Irritable child in mothers arms with prominent cough + Conjunctivitis, +/- cervical LN Erythematous MP rash whole body, most pronounced on
No palmar erythema, no puffy hands/feet
CRP=2, ESR=36 CBC unremarkable AST slight increase, ALT nl U/A with pyuria
◆ 2/16/15 ◆ 5
This child comes from a family with several
Just returned from the Philippines (became ill on
Exam Irritable child in mothers arms with prominent cough + Conjunctivitis, +/- cervical LN Erythematous MP rash whole body, most pronounced on
No palmar erythema, no puffy hands/feet Labs; CRP=2, ESR=36 CBC unremarkable AST slight increase, ALT nl U/A with pyuria
◆ 2/16/15 ◆ 6
Measles PCR throat positive
◆ 2/16/15 ◆ 7
◆ 2/16/15 ◆ 8
Potential for eradication (by 2020?) Several factors work in favor of measles eradication: humans are
the only hosts, measles vaccine is highly efficacious, and immunity resulting from infection and/or vaccination is very durable
3-4 million cases
~ 500,000 reported cases
Severe complications
4,000 encephalitis cases 150,000 respiratory complications (PNA)
48,000 hospitalizations 450 deaths
◆ 2/16/15 ◆ 9
Vaccine Licensed 1963
55,000 cases nationally
11,000 hospitalizations 123 deaths
◆ 2/16/15 ◆ 10
Introduction of 2nd dose of vaccine in 1989 and
2000: “Measles is no longer endemic in the
Record low annual total in 2004 (37 total cases in
Elimination of endemic measles in North and South
◆ 2/16/15 ◆ 11
Vaccine Licensed 1963
2nd dose
1989 Endemic transmission interrupted Measles declared eliminated
Africa, Asia, Pacific Rim countries and…
Europe
Several different countries with large outbreaks including 15,000 cases
in France in 2011
Romania, Ireland, the UK, France, Italy, and Spain also with outbreaks
◆ 2/16/15 ◆ 12
◆ D
5
◆ D
5
◆ D
4
◆ D
4
◆ D
4
Highly contagious viral illness – 90% of
Measles is transmitted via the airborne route Measles patients are infectious 4 days prior to
Persons who share the same air space at the same
◆ 2/16/15 ◆ 13
265-302.
Herd Immunity to Infectious Diseases. Nature 1985;318:323-9.
Herd Immunity. Lancet 1990;335:341-45.
Measles Airborne and probably the most infectious communicable disease: R0 =12-18
Measles transmission has been documented in:
Physician offices Emergency rooms Hospital wards Schools Airplanes Theme parks
◆ 2/16/15 ◆ 14
MMR vaccine can be given to exposed, susceptible contacts
Immunoglobulin (IG) can be given to exposed, susceptible
MMR is preferred for persons >12 months IG is preferred for infants (IM), pregnant women (IV) Quarantine is not indicated for persons who receive PEP in
A high-risk contact is defined as an exposed person who is at high-risk of measles
infection or complications (pregnant or immunocompromised) or who works in a sensitive setting (healthcare personnel of any age) or works in or attends a setting with known unvaccinated persons (e.g., school/childcare) or who had significant exposure to the case (household contact).
◆ 2/16/15 ◆ 15
Persons considered susceptible after assessment
Quarantine can be accomplished by:
Verbal instructions communicated to the exposed person, or A legal order of quarantine issued by the health officer
Active symptom monitoring, particularly for people
Quarantined people should be contacted at the end of the
quarantine period to determine their status
◆ 2/16/15 ◆ 16
Of 159 cases (Jan-Aug 2013)
157 (99%) import-associated 42 (26%) directly from 18 countries 21 (50%) from WHO European Region Imported cases resulted in outbreaks Some of these were quite large outbreaks
New York: 58 cases
City, 6 generations of measles, none had been vaccinated, contact investigation=3500!!
North Carolina: 23 cases
Texas: 21 cases
◆ CDC, MMWR, Sept 2013
At that time, 2nd largest number in US since measles
Most occurred in unvaccinated persons
◆ 2/16/15 ◆ 17
610 cases, 20 outbreaks
[by comparison 189 cases in 2013]
58 cases
54 (93%) import associated 13 directly imported Of the 13 imported
Philippines (8), India (2), Singapore (1), Vietnam (1), West
Europe (1)
Genotyping data
◆ 2/16/15 ◆ 18
Ca ses in California linked to travel to Disneyland Dec 2014-Jan 2015 Additional cases in other states—Utah, Texas, Colorado, Washington
Will now see several cases without Disneyland exposure
time period
◆ 2/16/15 ◆ 19
Measles genotype information was available from 9 measles cases; all were genotype B3 and all sequences linked to this outbreak are identical. The sequences are also identical to the genotype B3 virus that caused a large outbreak in the Philippines in 2014. During the last 6 months, identical genotype B3 viruses were also detected in at least 14 countries and at least 6 U.S. states, not including those linked to the current outbreak.
◆ 2/16/15 ◆ 20
Of 9 cases genotyped All B3 Same as strain
Also 14 countries 6 other states
What will the rest of the year bring?
Particularly problematic when measles introduced in pockets
May see clusters geographically and socially
◆ 2/16/15 ◆ 21
◆ 2/16/15 ◆ 22
Rash
2-4 days after prodrome, 14 days after
exposure
Maculo-papular, becomes confluent Begins on face and head and moves downward Persists 5-6 days Fades in order of appearance[copper] color
◆ 2/16/15 ◆ 23
◆ 2/16/15 ◆ 24
Occurs in partially immune individuals
Those who received IG (e.g., exposed infants), < 9 months of
age (because of maternal antibodies), occasionally in someone previously vaccinated/failure of vaccine (secondary vaccine failure) Characterized by milder illness than typical measles,
Prodrome shorter > regular measles Cough and coryza minimal Koplick spots-not present or only transient rash-same progression as regular measles but doesn’t become
confluent
◆ 2/16/15 ◆ 25
Journal of Infectious Disease 2011 Two case studies of modified measles in vaccinated physicians exposed to primary measles cases: high risk of infection but low risk of transmission. Rota JS1, Hickman CJ, Sowers SB, Rota PA, Mercader S, Bellini WJ.
In 2009, measles outbreaks in Pennsylvania and Virginia resulted in the exposure and apparent infection of 2 physicians, both of whom had a documented history of vaccination with >2 doses of measles-mumps-rubella vaccine. These physicians were suspected of having been infected with measles after treating patients who subsequently received a diagnosis of measles. The clinical presentation was non classical in regard to progression, duration, and severity. It is hypothesized that the 2 physicians mounted vigorous secondary immune responses typified by high avidity measles immunoglobulin G antibody and remarkably high neutralizing titers in response to intense and prolonged exposure to a primary measles case patient. Both of the physicians continued to see patients, because neither considered that they could have measles. Despite surveillance for cases among contacts, including unvaccinated persons, no
additional cases were identified.
◆ 2/16/15 ◆ 26
Developed classic measles [88 contacts] Four Secondary cases that had 2 MMRs and/or + serology
Different syndrome than modified measles Generally occurs in previously immunized persons
Most occur in those who received inactivated/
Often starts with fevers and HA, dry cough Rash-starts distal and progresses in cephalad
Respiratory distress with dyspnea common -PNA
Presumably due to delayed hypersensitivity to killed vaccine
◆ 2/16/15 ◆ 27
◆ 2/16/15 ◆ 28
Condition Percent reported Diarrhea 8% Otitis Media 7% Pneumonia 6% (viral or secondary bacterial) Encephalitis 0.1 Hospitalization 18% Death 0.2 (most often associated with pneumonia in children,
encephalitis in adult)
◆ Based on 1986-1992 surveillance data
◆ 2/16/15 ◆ 29
Still one of the leading causes of death among young
Global estimates:
20 million cases worldwide 150,000 deaths per year
◆ 2/16/15 ◆ 30
“Slow virus” of brain
Considered ‘rare’ Latency between acute measles and first symptoms of SSPE
~4-10 years Four disease stages
1st stage: Changes in personality and behavior, school failure 2nd stage: repetitive and frequent myoclonic jerks, seizures
and/or dementia
3rd stage: rigidity, extrapyramidal symptoms, Last stage: vegetative state, autonomic failure or akinetic
mutism
Survival period: 1-3 years ◆ Modlin JF, Pediatrics, 1977
◆ 2/16/15 ◆ 31
panencephalitis (SSPE), a fatal disease of the central nervous system that generally develops 7-10 years after infection. From 1989 through 1991, a resurgence of measles occurred in the United States, with 55,622 cases of measles reported. The purpose of the present study was to identify cases of SSPE that were associated with the resurgence of measles and to calculate the risk of developing SSPE.
were tested for the presence of measles virus RNA. Measles virus genotypes were determined by reverse-transcription polymerase chain reaction (RT-PCR) and by analysis of the sequences of the PCR
residing in the United States who had measles during 1989-1991.
with SSPE confirmed the diagnosis of SSPE. For 5 of the 11 patients with SSPE who had samples tested by RT-PCR and for 7 patients with SSPE who were identified in published case reports, it was determined that the development of SSPE was associated with the measles resurgence that occurred in the United States during 1989-1991. The estimated risk of developing SSPE was
10-fold higher than the previous estimate reported for the United States in 1982.
2000 4000 6000 8000 10000 12000 14000 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012
From California
Thailand Mexico Mexico Iraq Philippines India
◆ 2/16/15 ◆ 32
Blood Urine Nasopharyngeal or throat swab In California-many public health labs
◆ 2/16/15 ◆ 33
Specimens should be collected and tested promptly after
Positive serologic test for measles IgM antibody
Blood collected ≤ 72 hours of rash onset will have detectable IgM
in ~80% of measles cases
Nearly all measles cases with blood collected > 72 hours of rash
Detection of measles nucleic acid by polymerase
Nucleic acid can be detected on the same day as rash onset in
respiratory specimens and as late as 10 days in urine
No specific antiviral therapy available WHO recommends vitamin A for all children with
Vitamin A is administered once daily for two days, at the following doses: 50,000 IU for infants <6 months of age 100,000 IU for infants 6 to <11 months of age 200,000 IU for children >12 months of age
◆ 2/16/15 ◆ 34
1st dose of MMR 12-15 months, 2nd dose at 4-6
2%-5% of recipients do not respond to the first
Two doses of MMR vaccine offer >99%
Primary vaccine failures
No sero-conversion; no response to vaccine at all, individuals
will have typical measles course
~2-5% of individuals with first dose MMR, this is reason we
give 2nd dose MMR Secondary vaccine failures
Sero-conversion; develop measles but milder course (e.g.
modified measles)
◆ 2/16/15 ◆ 35
Mask patients immediately Do not allow in waiting room/common area All HCW need to wear N95 (CalOSHA) Do not use room > one hour after patient leaves If possible, schedule end of day Inform office/facility prior to entering facility
◆ 2/16/15 ◆ 36
Previously healthy, Hispanic male 6 weeks of age
Developed upper respiratory tract symptoms Seen in clinic for “stuffy nose” and told to use nasal saline
drops
During next 8 days had 2 additional visits to PMD and an ER
visit
2nd ER visit admitted to floor and within a few hours
transferred to PICU with pulmonary HTN
Died the following day: pulmonary HTN and WBC >130,000
Ultimately diagnosed with Bordetella pertussis
Several family members ill with “cold-like”
◆ 2/16/15 ◆ 37
Caused by Bordetella pertussis, a gram negative, fastidious,
Primarily a toxin-mediated disease; bacteria attach to cilia
Most severe disease and death occurs in infants <4 months
Highly infectious during catarrhal phase and first two
R0 estimated to be 15-17 (similar to measles)
◆ 2/16/15 ◆ 38
Humans are the only host Transmitted by short-range respiratory aerosols Not thought to be transmitted by fomites Incubation period ~7-10 days (5-21) Occurs year-round but some seasonal peaks in late
Neither infection nor immunization confers life-long
Prior to vaccine era, >200,000 cases
Still a major problem in developing countries,
Outbreaks in the U.S. have “ballooned” in specific
CA experienced pertussis epidemic in 2010;
◆ 2/16/15 ◆ 39
Nearly all other states experienced peaks in disease
Nationally in 2012
Highest number of cases for >50 years 18 deaths
DTP Tdap DTaP
◆ SOURCE: CDC, National Notifiable Diseases Surveillance System and Supplemental Pertussis Surveillance System and 1922-1949, passive reports to the
Public Health Service ◆ *2011 data have not been finalized and are subject to change. 2011 data were accessed on July 5, 2012.
◆ 2/16/15 ◆ 40
◆ 2/16/15 ◆ 41
(outside neonatal period) 3 stages: catarrhal, paroxysmal, and convalescence Classical presentation
coryza; no pharyngitis
paroxysmal cough, posttussive vomiting and “whoop” no systemic illness and no fever
Cough often quite prolonged and severe Adults with pertussis often report sweating episodes
◆ 2/16/15 ◆ 42
Infant initially looks deceptively well; coryza, no or
Later:
Gagging, gasping Bradycardia or apneic episodes Cyanosis (parents may report red or purple face) Posttussive emesis
Infants can develop very high WBC with lymphocytosis Adenovirus or RSV co-infection can occur
Pneumonia Seizures Respiratory distress Encephalopathy Death
◆ 2/16/15 ◆ 43
Culture: considered gold standard and very specific but
insensitive, not timely
PCR: increased sensitivity > culture, more rapid
Ct cut off values are important; contamination of NP swabs with pertussis
vaccine DNA can lead to false positives*
Serology: useful for adolescents & adults in the later stages of
the disease, but is not currently considered valid laboratory confirmation for surveillance purposes
*See: http://www.cdc.gov/pertussis/clinical/diagnostic-testing/diagnosis-pcr-bestpractices.html
Study from Argentina
41 infants with pertussis; 9 infants with ET 4 before 2011, considered “rescue Rx”; all died 5 done “preemptively” (WBC>95k), 4 of these infants survived
◆ 2/16/15 ◆ 44
◆ The Pediatric Infectious Disease Journal
Volume 32, Number 6, June 2013
◆ 2/16/15 ◆ 45
◆ 2/16/15 ◆ 46
The birth of the modern American anti-vaccine
The documentary contended that the whole-cell
Concerns about the safety of whole cell pertussis
In the U.S., whole-cell pertussis (wP) vaccines were phased out in the
1990s due to vaccine safety concerns; in 1992 acellular pertussis (aP) vaccine was recommended for the 4th and 5th doses of the childhood series and in 1997 aP vaccine was recommended for the entire series
Acellular vaccines (subunit, purified inactivated components) are less
reactogenic than whole-cell vaccines
DTaP (pediatric formulation) 6 weeks-7 years (2,4,6 months, 15-18 months, 4-6 years) Tdap (adolescent and adult formulation) >10 years (Boostrix) >11 years (Adacel)
◆ 2/16/15 ◆ 47
Immunity wanes rapidly after aP* vaccine booster at
Vaccine effectiveness is high for only ~2 years
wP* vaccine induces Th1 and Th2 response (and
Retrospective data
1 dose wP in infancy confers better protection vs. later
exposure vs. aP (Klein N, NEJM, 2012)
*aP=acellular pertussis vaccine, wP=whole cell pertussis vaccine
They probably play only a minor role Other causes are more likely:
Strain changes (change in circulating organisms, in alleles for
each antigen, replacement of older promoters of PT allele, pertactin-deficient strains)
aP* less efficacious than wP* aP has predilection to induce Th2 response (rather than Th1) ?aP protects against disease, but not infection, in a baboon
model permitting infected people to transmit the bacteria
*aP=acellular pertussis, wP=whole cell pertussis vaccine Plotkin S, Clin Inf Dis 2013
◆ 2/16/15 ◆ 48
General availability of more
More rapid waning of vaccine-
Genetic changes in B.
Treatment effective for limiting infectivity, but
Prophylaxis
Identifying contacts difficult Long infectious period Large Ro One strategy is to target prophylaxis to those at highest risk
with infants
◆ 2/16/15 ◆ 49
ACIP and ACOG recommend that all pregnant
Antibodies to pertussis (PT, FHA, PRN, FIM) are actively
transported across the placenta to the fetus1,2 CDC feels this is the most important strategy to
◆ 1. de Voer RM, et al. Seroprevalence and placental transportation of maternal antibodies specific for
Neisseria meningitidis serogroup C, Haemophilus influenzae type B, diphtheria, tetanus, and pertussis. Clin Infect Dis. 2009 Jul 1;49(1):58-64.
◆ 2. Gall SA, et al. Maternal immunization with tetanus-diphtheria-pertussis vaccine: effect on maternal and
neonatal serum antibody levels. Am J Obstet Gynecol 2011;204
Data from Australia indicate that infants born to women
Data from UK’s recently implemented Tdap program for
VE ~90% in preventing disease in infants up to 2 months of age Vaccine coverage among pregnant women now ~60% No increase in pregnancy adverse events
meeting.
◆ 2/16/15 ◆ 50
14 month old male presents with ~1 week+ of fever,
And ~2 days of progressive swelling and tender
◆ 2/16/15 ◆ 51
Past medical history
Previously healthy UTD on all vaccines including MMR Serology was drawn and respiratory sample collected Mumps IgM “positive” Respiratory sample: PCR positive for parainfluenza virus type 3 So…is this mumps or not?
Caused by mumps virus, a paramyxovirus Symptoms typically appear 16-18 days after exposure
Typical course
Fever, headache, muscle aches, fatigue, and decrease appetite A few days later, salivary gland enlargement (unilateral or
bilateral) - aka “chipmunk cheeks”
◆ 2/16/15 ◆ 52
Transmitted by contact with respiratory secretions
Droplets from the respiratory tracts of infected
◆ 2/16/15 ◆ 53
Face-to-face (<3 feet) contact with an infectious person
Usually 16 to 18 days, but cases may occur 12 to 25 days
Highly infectious R0 = 10-12 90-92% needed for herd immunity Communicability is highest from 2 days before to 5 days
Only cause of epidemic parotitis Sporadic parotitis can be caused by:
Cytomegalovirus Parainfluenza virus types 1 and 3 Influenza A virus Coxsackieviruses and other enteroviruses Lymphocytic choriomeningitis virus Human immunodeficiency virus Staphylococcus aureus Nontuberculous Mycobacterium
◆ 2/16/15 ◆ 54
Journal Infect Dis, 2013 What they found; 101 specimens (all) [<18 years] EBV (23)[8] HHV-6B (10)[8] HPIV-2 (3)[3] HPIV-3 (1)[0]
Human bocavirus (1)[1]
No mumps or EV
Up to 20% of infections asymptomatic 40-50% of infections may have nonspecific or respiratory
Prodromal symptoms are nonspecific
Myalgia, anorexia, malaise, headache and low-grade fever
Most common manifestation is unilateral or bilateral
Parotitis tends to occur within the first 2 days and may be first noted
as earache and tenderness on palpation of the angle of the jaw
Symptoms decrease after 1 week and usually resolve after 10 days
◆ 2/16/15 ◆ 55
Central nervous system (CNS) involvement is
Meningitis Encephalitis
Other rare complications include arthritis, mastitis,
Pancreatitis (2-5%) Orchitis (testicular swelling) is a common complication and
Females can develop inflammation of ovaries, tender
◆ 2/16/15 ◆ 56
Mumps serum IgM positivity; OR Four-fold rise between acute and convalescent
Isolation of mumps virus; OR Detection of viral RNA by reverse transcription
Specimen collection
Collection of a serum specimen for serologic detection of mumps
antibody in conjunction with obtaining a buccal swab for molecular determination is helpful in the laboratory confirmation of a mumps case
IgM/IgG testing
Collect 7-10 ml of blood in a red top or serum separator tube (SST). Serum should be collected as soon as possible after onset of parotitis
for IgM testing or as the acute-phase specimen for determining seroconversion
If initial testing is negative and mumps is strongly suspected, a
convalescent serum sample should be collected 2-3 weeks after symptom onset
◆ 2/16/15 ◆ 57
In vaccinated persons:
IgM may be falsely negative in infected persons
May be transient, late occurring, or missing in persons
Presence of IgG prior to infection does not
In unvaccinated persons:
IgM antibody detectable within 5 days of onset, reaches a
maximum level about a week after onset, and remains elevated for several weeks or months False positive mumps IgM results can occur from:
parainfluenza virus 1, 2, and 3, Epstein-Barr virus, adenovirus,
and human herpesvirus 6 infections
This case had no known contact with other known
Parainfluenza positive probably more likely
However, there have been recent cases and
◆ 2/16/15 ◆ 58
Midwest outbreak 2006
6,584 cases in 11 states Predominantly Midwestern college students, especially those
living in dorms.
Most (90%) had a history of 2 MMRs 79% had received 2nd MMR >10 years prior
New York/New Jersey outbreak 2009-2010
>2,700 cases Primarily Hasidic Jewish communities
Both outbreaks were likely sparked by person who
◆ 2/16/15 ◆ 59
I S I T R E A L L Y O N L Y A P E R S O N A L D E C I S I O N ? W H A T I S T H E I M P A C T O N O T H E R S ?
KQED January 2015
Rhett Krawitt, 6, outside his school in Tiburon, Calif. Seven percent of the children in his school are not vaccinated. Courtesy of Carl Krawitt
◆ 2/16/15 ◆ 60
Carl Krawitt has watched his son, Rhett, now 6, fight
Rhett cannot be vaccinated…..it may be months
But Rhett lives in Marin County, Calif., a county with
◆ 2/16/15 ◆ 61
At his child’s school board meeting someone
"It's really important your kids don't bring
◆ 2/16/15 ◆ 62
◆ 2/16/15 ◆ 63
Theory, Practice. Epidemiologic Reviews 1993;15(2):265-302.
Vaccination and Herd Immunity to Infectious Diseases. Nature 1985;318:323-9.
Immunization and Herd Immunity. Lancet 1990;335:341-45.
◆ Endemic in Pakistan
Nigeria and Afghanistan
◆ 2/16/15 ◆ 64
◆ 2/16/15 ◆ 65
January 26, 2014 (from CDPH IZB website)
Local Health Epi link to Disney No Epi link Total Alameda 3 2 5 San Mateo 2 2 Santa Clara 2 2 Los Angeles 9 2 11 Long Beach 2 2 Orange 12 11 23 Pasadena 2 2 Riverside 4 4 San Bernardino 4 4 San Diego 13 13 Ventura 1 4 5 Total 73
time period
◆ 2/16/15 ◆ 66
Before widespread immunization for measles, there were
First measles vaccine was licensed in 1963 By 1966, ~24% of California children <10 years of age
Intensive vaccination campaigns occurred in 1966-1967 School law in 1968
Contact investigation ensued
839 potentially exposed 11 additional measles cases resulted Mostly in unvaccinated infants and children 10 months - 9 years
2 were unvaccinated siblings of patient 5 were unvaccinated school contacts 4 were children exposed in pediatrician’s office (3 of these were
infants <12 months of age)
infant and family had to stay ‘quarantined’ in hotel room while in Hawaii
◆ 2/16/15 ◆ 67
◆ 2/16/15 ◆ 68
◆ 2/16/15 ◆ 69
Non-human primate model (baboons) Disease in baboons very similar to severe clinical
2 week ‘heavy respiratory colonization’ WBC 30-80k Paroxysmal cough illness (average >2 weeks but < children) Characterization of airborne transmission of B. pertussis from
infected naïve animals Test hypothesis: aP fails to prevent B. pertussis
Conclusion from baboon study
aP vaccine protects against severe disease However, it does not protect against carriage/infection
Implications for humans
Need additional study but this suggests “Plausible” explanation for resurgence No ‘herd immunity’ and therefore vaccinated individuals could
be infected (and not know it) and transmit it…
(Potential) implications for Cocooning strategy Healthcare workers Still too soon to know
◆ 2/16/15 ◆ 70
Mechanism for pathogenesis of pulmonary hypertension in infants with pertussis
◆ Paddock C, Clin Infect Dis, 2008
◆ -3 ◆ 0 ◆ 2 ◆ 12 ◆ 8
◆ Symptom Onset ◆ Incubation Period ◆ Catarrhal Stage ◆ Paroxysmal Stage
◆ Convalescent
Stage ◆ Communicable Period