Contagious, vaccine preventable infection caused by bacterium Bordetella pertussis.
A worldwide cyclic infection, known as whooping cough.
Pertussis is caused by Bordetella pertussis, a fastidious gram-negative coccobacillus that is a human pathogen without known or environmental reservoirs.
Pertussis is spread by respiratory droplets.
The incubation period for pertussis is typically 7 to 10 days, longer than that with common viral upper respiratory infections of 1 to 3 days.
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.
in 2024 there were more than 34,000 cases reported, including 10 deaths.
Currently more than half of pertussis cases occurred in adolescents and adults, who serve as a transmission reservoir to infants and children.
Infants younger than one year have the highest incidence of infection about 23 cases for 100,000 in 2023 and are at greatest risk for complications – apnea, pneumonia, seizures, and mortality, accounting for 89% of pertussis related deaths.
Immunization of pregnant women can induce maternal antibodies that can be passively protective of infants.
Routine vaccination of pregnant females is recommended to impart to the newborn infant passive immunity against protesters for the first six months.
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.
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.
Pertussis infection has three clinical phases.
The initial catarrhal phase lasts less one to two weeks and his characterized by nonspecific symptoms, such as malaise, rhinorrhea and mild cough.
The paroxysmal phase with its characteristic symptom of paroxysmal cough, involving repetitive vigorous coughs, lasts 2 to 3 months.
Prolonged cough paroxysms may be followed by a forceful inspiration which can cause the characteristic whooping sound.
Severe coughing may cause urinary incontinence, rib fractures, and in adults complications include pneumonia and need for hospitalization.
The severity of coughing gradually diminishes and resolves during the convalescent phase.
Fever occurs only an 8 to 12% of adults.
A prior pertussis infection or immunization may attenuate illness severity with cough, persistenting more than two weeks.
Among adults presenting with prolonged cough the estimated prevalence of pertussis is 12 to 32%.
Acellular and whole cell vaccines are very efficacious during the first 2years after vaccination.
Acellular vaccine for pertussis is less effective and results in a brief period of immunity.
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.
Diminished duration of protection is afforded by childhood acellular vaccine (DTaP) compared with diphtheria and tetanus toxoids and whole cell pertussis (DTwP) vaccine.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.
Diagnosis: Diagnosis should be suspected in patients with Cough of any duration with paroxysm, inspiratory Whoomp or post tested emesis.
Laboratory tests available to diagnose pertussis include nasopharyngeal culture, polymerase chain reaction testing of nasopharyngeal specimen and serological assays.
Treatment:
The initiation of treatment occurs before test results anre available, with the appropriate clinical suspicion, and for individuals who have contact with others at risk for severe disease as well- infants and young children.
Azithromycin and erythromycin are effective treatments.
Prevention:
The tetanus, diphtheria, a cellular prothesis (Tdap) vaccine is safe and 92% effective at preventing ptosis infection.
Studies of adolescents found the Tdap vaccine efficacy to be 73% within one year but decline to 34% after 2 to 4 years.
For unvaccinated adults, a primary vaccination schedule is followed by either TD orTdap vaccine at least four weeks later and subsequently at 6 to 12 months.
Because immunity wanes after childhood vaccination and infection a one timeTdap boost of vaccine is recommended for all people at any time after age 11 years.
All household contacts should receive post exposure, antibiotic prophylaxis, regardless, if they have vaccination history.