Whooping cough hits hardest among young babies, data show

Babies have been hardest hit by whooping cough in California, according to new statistics released by the state Department of Public Health.

FOR THE RECORD:
Whooping cough: A headline on a Sept. 17 LATExtra article incorrectly tied flu shots to protection against whooping cough, also known as pertussis. Health officials are urging pertussis vaccinations for anyone who will be in contact with babies. In addition, officials have begun their annual push to urge people to seek seasonal flu shots.

All nine deaths so far this year have been among infants younger than 3 months. Among patients who are critically ill with the disease, babies have also been disproportionately hospitalized.

According to the data released late Wednesday, of 196 patients known to have been hospitalized with whooping cough in California, 74% were infants younger than 6 months and most — 57% — were younger than 3 months.

Whooping cough, also known as pertussis, is often spread to babies by parents, siblings, aunts, uncles and other adults, and public health officials warn that many people are not fully immunized. Because infants do not begin vaccinations until they are 2 months old, health officials for months have been urging anyone who expects to be in contact with babies — especially pregnant women — to get vaccinated.

“People with respiratory conditions and cold-like conditions should not have contact with small infants,” said Dr. Jonathan Fielding, director of the Los Angeles County Department of Public Health.

Although whooping cough is spreading among adults too, those cases often are not diagnosed.

State data as of Tuesday show that California has had the most cases of whooping cough since 1955, with 4,017 confirmed, probable and suspect cases reported so far this year. The rate, 10.3 cases per 100,000 people, is the highest incidence since 1962.

Health officials also released demographic information showing that 77% of the hospitalized infants younger than 6 months were Latino, as were eight of the nine fatalities.

Health officials said they believe the overrepresentation of very young Latino babies is tied to the larger than average size of many Latino families and more frequent visits among family members than with other groups. Because of those factors, authorities said Latino infants are more likely to be exposed to someone with whooping cough.

Infants younger than 6 months are among the most susceptible to whooping cough because they are too young to have received the three inoculations needed to give them considerable protection from the disease. Vaccination guidelines call for shots at 2, 4 and 6 months.

Ken August, a spokesman with the California Department of Public Health, said the rates of immunization for Latino children are high and after 6 months of age, hospitalization rates drop for Latinos. State data show that, overall, whites were the most likely group to be affected by whooping cough.

State health officials briefed reporters Thursday on pertussis and began their annual push to urge vaccination for the flu, which usually spreads in the fall and winter but is already circulating sporadically in the state.

“The sooner you get vaccinated, the better,” state epidemiologist Dr. Gil Chavez said, because it takes two weeks for the vaccine to begin working after the inoculation.

Anyone 6 months of age or older should receive this season’s flu shot or nasal mist, Chavez said. Unlike last year, supplies of the vaccine, which protects against H1N1 and seasonal flu, are plentiful.

Officials said people should realize that vaccinations received last year do not offer protection now, meaning that new inoculations are needed.

ron.lin@latimes.com