Contagious, vaccine preventable infection caused by 2242e US.
A worldwide cyclic infection.
Incidence is highest in infants too young to have completed their primary immunizations series which is six months or younger, and who are at highest risk for developing life-threatening complications.
In high income countries, pertussis related mortality occurs predominately in infants of three months or younger age.
Before vaccine availability 270,000 cases were diagnosed annually in the US, and as many as 10,000 deaths per year, mainly among infants.
Immunization of pregnant women can induce maternal antibodies that can be passively protective of infants.
Complications include pneumonia, cardiovascular compromise, seizures, encephalopathy can occur and this especially true for infants below the age of 1 year.
Deaths most common among infants.
Neonates and infants are at increased risk of pertussis related hospitalization
and deaths compared with older children and adults.l
Number of cases increasing in recent years.
16,858 cases were reported in 2009 with 12 infant deaths.
27,550 cases reported in 2010.
Increasing rates in adolescents.
Case fatality 1.8% for newborns and infants less than 2 months of age.
Infants acquire infection from adults undiagnosed disease.
Acellular and whole cell vaccines are very efficacious during the first 2years after vaccination.
Acellular Vaccine T Dap reduced dose gives no more than moderate protection against disease in the first year and protection then wanes rapidly over 2-3 years.
Acellular vaccines contain several specific antigens.
Whole cell vaccines are suspensions of killed B. pertussis organisms.
Tdap ( tetanus toxoid, reduced diphtheria toxoid and acellular pertussis) vaccine improves immunity against pertussis but presently coverage of this vaccine is 56% among adolescents and less than 6% among adults.
Presently recommended that Tdap be given as a single dose for persons ages 11 through 18 who have completed the recommended childhood diphtheria and tetanus toxoid and pertussis/diphtheria and tetanus toxoids and acellular pertussis vaccination series and for adults ages 19 to 64 years.
It is recommended that pregnant women receive tetanus, diphtheria, and acellular pertussis (Tdap) vaccine every pregnancy during weeks 27 through 36 of gestation period
The recommendation is for 5 doses of DTaP.
Most children receive the fifth dose of DTaP between 4-6 years of age.
Protection against pertussis wanes during the five years after the fifth dose of DTaP (Klein NP et al).
Tdap vaccine recommended for pregnant women during each pregnancy
regardless of prior immunization status.
In the above study the risk of pertussis increased by 42% each year after the fifth DTaP dose.
Since the 1980s outbreaks have occurred every 3-5 years, with increased peak incidence which each successive outbreak.
Pregnant females should get a dose with each pregnancy regardless of time of previous vaccination to protect the newborn.