DefinitionFor surveillance purposes, pertussis is a cough illness lasting at least two weeks with one of the following: paroxysms of coughing, inspiratory "whoop," or post-tussive vomiting, with or without laboratory evidence of infection.
NumeratorNumber of pertussis cases reported in Utah (including cases identified in outbreak settings).
DenominatorTotal Utah population per year.
Why Is This Important?According to the Council for State and Territorial Epidemiologists, "''Bordetella pertussis'' is the most poorly controlled bacterial vaccine-preventable disease in the U.S." Controlling pertussis is a difficult challenge addressed by increasing vaccination rates, prompt identification, decreasing contact between infected and non-infected individuals, and treatment of ill individuals.
Pertussis is a contagious, bacterial, respiratory disease. Although pertussis may be a mild disease in older children and adults, these infected people may transmit the disease to other susceptible persons, including unimmunized or incompletely immunized infants. Young infants are at highest risk for acquiring pertussis and pertussis-associated complications, such as pneumonia and inflammation of the brain.
Although not common, pertussis can cause death, especially in children under one year of age. Most children are protected against pertussis by vaccination during childhood; however, immunity decreases over time and leaves adolescents and adults unprotected. National figures reported by the CDC indicate that infants aged less than one year, who are at greatest risk for severe disease and death, continue to have the highest reported rate of pertussis. School-aged children from 7-10 years of age continue to contribute a significant proportion of reported pertussis cases.
In 2005, the FDA approved Tdap, a pertussis vaccine for adolescents and adults. The rate of pertussis decreased in the years following approval of Tdap. However, there is evidence indicating that the highest level of protection from the Tdap booster lasts around two years then decreases over time. This has also been observed in individuals that have become infected with pertussis; these individuals are protected for a few years, but then their immunity becomes less effective over time. This decreasing immunity is called waning immunity.
Healthy People Objective IID-1:Reduce, eliminate, or maintain elimination of cases of vaccine-preventable diseases
U.S. Target: Not applicable, see subobjectives in this category
Other ObjectivesHealthy People 2020 IID-1 sub-objectives related to pertussis:
IID-1.6: Reduce cases of pertussis among children under 1 year of age [[br]]
'''U.S. Target:''' 2,500 cases[[br]]
'''State Target:''' 31 cases per year
IID-1.7: Reduce cases of pertussis among adolescents aged 11 to 18 years[[br]]
'''U.S. Target:''' 2,000 cases[[br]]
'''State Target:''' 58 cases per year
How Are We Doing?Pertussis has been on the rise in Utah steadily since 2009, with a notable increase in cases beginning in 2011. 2012 data indicated that pertussis activity reached pre-vaccine era rates with 55.8 cases per 100,000 person-years. Consistent with the cyclical trend of pertussis, Utah's pertussis activity decreased in 2013 to 45.5 cases per 100,000 person-years and then decreased again in 2014 to 31.9 cases per 100,000 person-years and has continued to decrease in 2015 with 16.8 (N=502) cases per 100,000 person-years. In 2016, Utah's pertussis rate decreased to 9.1 (n=271) per 100,000 person-years.
There are several factors that may be contributing to the increase of pertussis rates in recent years, including: actual increases in disease occurrence, better laboratory tests, increased recognition by clinicians, the cyclical nature of pertussis peaking every 3-5 years, waning immunity of the adult booster (Tdap) around two years after the vaccine is given, and the higher risk of infection with pertussis in individuals who are not vaccinated (who have an eight-fold greater risk if exposed).
Incidence rates for Utah in 2016 showed a 7.7% decrease compared to the incidence rate in 2015. Age distribution data for 2016 indicates that 59.2% of cases are age 19 years and younger. The incidence rates are highest in infants less than one year of age at 41.5 cases per 100,000 person-years, (n=21). Pertussis incidence in adolescents between the ages of 5-14 years was 11.1 per 100,000 person-years (n=60).
How Do We Compare With the U.S.?Throughout the 1990s and up through 2004 (with the exception of 1998, when a statewide outbreak of pertussis occurred in Utah), the rate of pertussis in Utah mirrored national trends. Utah pertussis rates began to climb in 2005, and in 2006 Utah had a rate of pertussis nearly six times the national average. However, in Utah a substantial decrease in the rate of pertussis occurred in 2007 and continued to decline to near the U.S. average in 2008. Pertussis began to increase again in 2009 with rates remaining above the national average. 2012 data showed national rates to be double what they were in 2011, which was the same trend seen in Utah. However, Utah rates have been substantially higher than national rates since 2011. Pertussis rates in Utah remain higher than national levels, as seen in as seen in the 2016 provisional national data.
What Is Being Done?Surveillance data are used to identify persons or areas in which additional efforts are required to reduce disease incidence. Surveillance data help to promptly identify outbreaks in which prophylaxis (treatment to prevent or mitigate disease) of contacts can help limit the spread of disease. Surveillance data are also used in evaluating vaccination policies at the state level.
Childhood immunization is the most effective weapon against pertussis infection. The UDOH Immunization Program works with parents, physicians, and local health departments to provide immunization histories for all children under age two years and remind parents when vaccinations are due.
The adult pertussis vaccine (Tdap) is recommended for adolescents aged 7-18 years. Also, routine use of a single dose of Tdap for adults over 19 years of age is recommended to replace the next booster dose of tetanus and diphtheria toxoids vaccine (Td). Tdap is also recommended for adults who have close contact with infants less than one year of age.
The Bureau of Epidemiology conducts ongoing statewide surveillance of pertussis cases. Per Communicable Disease Rule R386-702-3, health care providers and laboratories are required to report suspected cases of pertussis to the Bureau of Epidemiology or the local health department within three business days of identification. The Bureau of Epidemiology assists local health departments with the investigation of cases and implementation of control measures to prevent further cases.