Washington state on track for major pertussis epidemic
Public health officials in Washington state have confirmed more than 1,100 cases of whooping cough so far this year in what is on track to become the worst epidemic of the disease to hit the state in seven decades.
No deaths have been reported from this year’s outbreak but 20 infants have been hospitalized with the bacterial infection, which poses a special risk to young children, said Tim Church, a spokesman for the state Health Department.
Governor Christine Gregoire made state emergency funds available on Thursday to help increase vaccinations against the disease and announced federal approval to redirect some funds to buy 27,000 more doses of vaccine for uninsured adults.
Whooping cough, also known as pertussis, causes severe, uncontrollable coughing. Worldwide, it infects between 30 million and 50 million people a year and kills about 300,000 - mostly children in the developing world.
In the United States, most children are immunized against whooping cough with a vaccine that is given as a series of shots starting at the age of two months.
Pertussis, also known as whooping cough, is a highly contagious infection of the respiratory tract caused by a bacterium called Bordetella pertussis. Pertussis is the second most frequently reported, vaccine-preventable disease in Canada.
During 2005 and 2006, about 2500 cases were reported annually.
The most noticeable symptom of this infection is severe spells of cough, followed by a “whoop” sound before the next breath.
The disease can affect people of any age; however, the disease is most severe among young infants. Infants under one year of age and pregnant women in their third trimester are most vulnerable to the effects of pertussis.
In some cases, pertussis can cause serious complications and even death in infants.
Immunization is the best defence against pertussis. Although widespread immunization has significantly decreased infection rates overall, cases still occur.
Outbreaks in the United States tend to run in cycles, but Church said the latest wave of cases in Washington state was running well above typical peak years in the past, when 500 to 600 cases might be reported for an entire year.
“We’re seeing 100 to 125 new cases every week,” he said, adding that at the current pace, Washington could end 2012 with about 3,000 cases, which would be the highest number the state has seen since the 1940s. “Our hope is that we can stem this tide and not let that happen.”
How can Pertussis be prevented?
The best way to protect against infection is to ensure that both you and your child are fully immunized. A child under six years needs five doses of the Pertussis vaccine, starting at two months of age, to be fully immunized. An additional booster dose, combined with tetanus and diphtheria (Tdap) vaccine, is given routinely to adolescents between 14 to 16 years of age across Canada.
It is recommended that adults not previously immunized against pertussis receive one dose of the Tdap vaccine. Consult your health care provider if you are unsure if you have been immunized against pertussis.
You should see your health care provider if anyone in your household has a cough that lasts longer than a week. It is important to get an accurate diagnosis, and to make sure infected individuals get treatment and avoid close contact with young children.
Proper hand washing may prevent the spread of pertussis, as well as other infectious diseases.
The current epidemic appears to have begun last year.
Infants born prematurely and patients with underlying cardiac, pulmonary, neuromuscular, or neurologic disease are at high risk for complications of pertussis (eg, pneumonia, seizures, encephalopathy, death). Older children, adolescents, and adults often have mild or atypical illness. Approximately one half of adolescents with pertussis cough for 10 weeks or longer. Complications among adolescents and adults include syncope, sleep disturbance, incontinence, rib fractures, and pneumonia.
Compared with older children and adults, infants younger than 6 months with pertussis are more likely to have severe disease, to develop complications, and to require hospitalization. From 2001-2003, 69% of infants younger than 6 months with pertussis required hospitalization.
Pneumonia, either from B pertussis infection or from secondary infection with other pathogens, is a relatively common complication, occurring in approximately 13% of infants with pertussis.
CNS complications such as seizures and encephalopathy are less common and are thought to result from severe paroxysm-induced cerebral hypoxia and apnea, metabolic disturbances such as hypoglycemia, and small intracranial hemorrhages.
Reported deaths due to pertussis in young infants have substantially increased over the past 20 years. From 1990-1999, the case fatality rate was approximately 1% in infants younger than 2 months and less than 0.5% in infants aged 2-11 months. Pertussis has been reported as a cause of sudden infant deaths.