California: Pertussis Rising (Again)

Credit CDC’s Pertussis page.

 

Key Points:

• 5/30/14 - California Warns on Rising Pertussis Cases

 

# 8688

 

In June of 2010 we started to follow what would end up being the worst Pertussis (Whooping cough) outbreak in the State of California (see California: Pertussis Epidemic) in at least a half century.  

 

During the summer and fall we revisited the outbreak (see here, and here), and in December the State of California released the following summary:

 

Pertussis Report

December 15, 2010

New in this report: Disease activity is slowing statewide, however relatively high numbers of cases continue to be reported each week

7,824 confirmed, probable and suspect cases of pertussis with onset from January 1 through December 15, 2010 reported to CDPH for a state rate of 20.0 cases/100,000.

527 new cases have been reported to CDPH since November 30 (Figure 1).

This is the most cases reported in 63 years when 9,394  cases were reported in 1947, a peak year,and the highest incidence in 52 years when a rate of 26.0 cases/100,000 was reported in 1958. Previously, the peak was in 2005 when there were 3,182 cases reported (Figure 2).

 

By the time all of the numbers were in for 2010, the number of cases had exceeded 9,000, including 10 deaths.  Since then, Pertussis numbers in California have remained elevated – particularly when compared to the the 1970s, 1980s, and 1990s – but not record setting.

 

 

During my parent’s day, whooping cough infected more than a 250,000 Americans each year, and killed about 5,000 of them. All that began to change in the 1940s when the first whole-cell pertussis vaccine - combined with diphtheria and tetanus toxoids (DTP) - was introduced.

 

It what was such remarkable success, that by the time my daughter was born (1977) the number of reported cases had just reached a record-low of 1,010 cases, a decrease of 99%.

 

But since then, the number of cases has increased dramatically, with 2012 seeing nearly 50,000 cases reported in the United States.

Credit CDC

 

 

The reasons behind these increases are complex, and not entirely understood, but some factors are believed to be:

• lower vaccination uptakes in children and adults
• the move away from whole cell pertussis vaccines to safer (but somewhat less protective) acellular vaccines in the 1990s
• evolutionary changes in the Bordetella pertussis bacteria.

 

Whooping cough outbreaks are cyclical, and we see localized outbreaks increase every three to five years.  As it has been four years since the last major epidemic in California, there are concerns that this year could be another banner year for the disease.

 

This from the California Department of Public Health.

 

Whooping Cough Cases Increase

Date: 5/30/2014

Number: 14-051

Contact: Anita Gore - (916) 440-7259

SACRAMENTO

Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state health officer, today warned that the number of pertussis (whooping cough) cases continue to increase in California.

CDPH has received reports of 2,649 cases of pertussis occurring from January through May 27, 2014, more than the number of cases reported in all of 2013. More than 800 cases were reported in April alone, the highest monthly count since the 2010 epidemic.

“The number of pertussis cases is likely to continue to increase,” says Dr. Ron Chapman. “As an important preventive measure, we recommend that pregnant women receive a pertussis vaccine booster during the third trimester of each pregnancy, and that infants be vaccinated as soon as possible.”

Infants too young to be fully immunized remain most vulnerable to severe and fatal cases of pertussis. Sixty-six of the hospitalized cases to date in 2014 have been in children four months of age or younger. Two infant deaths have been reported this year, one with onset in 2013, the second with onset in 2014.
Eighty-three percent of the cases have occurred in infants and children younger than 18 years of age. Of the pediatric cases, 8 percent who were younger than 6 months-old and 70 percent were 7 through 16 years of age.
It’s important that both children and adults are up-to-date on their immunizations. Booster shots for pertussis are critical because, unlike some other vaccine-preventable diseases, neither the pertussis disease nor vaccine offers lifelong immunity.

To prevent pertussis, CDPH recommends that: 

• Pregnant women receive a pertussis vaccine booster during the third trimester of each pregnancy, even if they’ve received it before.                        
• Infants be vaccinated against pertussis as soon as possible. The first dose is recommended at two months of age but can be given as early as 6 weeks of age during pertussis outbreaks. Children need five doses of pertussis vaccine by kindergarten (ages 4-6).
• California 7th grade students receive the pertussis vaccine booster as required by state law.
• Adults receive a one-time pertussis vaccine booster, especially if they are in contact with infants or if they are health care workers who may have contact with infants or pregnant women.

The symptoms of pertussis vary by age. For children, a typical case of pertussis starts with a cough and runny nose for one to two weeks. The cough then worsens and children may have rapid coughing spells that end with a whooping sound. Young infants may not have typical pertussis symptoms and may have no apparent cough. Parents may describe episodes in which the infant’s face turns red or purple. For adults, pertussis may simply be a cough that persists for several weeks.

Pertussis numbers will be updated every two weeks on the CDPH website.

 

  
Globally, Pertussis remains a serious public health issue, with the World Health Organization estimating that in 2008 about 16 million people were infected, and roughly 195,000 children died from the disease (cite).  And much like we discussed yesterday with measles, Pertussis can be reintroduced into a susceptible population by unvaccinated international travelers coming from areas where the disease is endemic.

 

But the truth is, with anywhere between 10,000 and 50,000 cases being reported in the United States each year, you don’t have to travel far to be exposed.  

 

Pertussis, after decades of near elimination, is a disease that is once again available locally.