Swine flu remains widespread in California but is abating
California is one of only seven states where H1N1 influenza is still widespread, but a variety of indicators suggest that this wave of the pandemic is abating even here, Dr. Mark Horton, director of the state Department of Public Health, said at a news conference Thursday.
FOR THE RECORD:
Flu vaccination: An article in Friday’s Section A on the H1N1 vaccine said that California had received more than 12 million doses and that there was enough available now for anyone who wanted it. That statement, attributed to Dr. Mark Horton, director of the state Department of Public Health, assumed that not every Californian would immediately want the vaccine. Although the state has more than 36 million residents, influenza vaccination rates usually average 30% nationwide. —
Hospitalizations for flu declined last week for the third week in a row, and visits to physicians’ offices for flu-like illnesses also dropped. The only indicator that did not drop was deaths from flu, but that typically lags a couple of weeks behind other indicators.
Despite the declines, Horton, like most other public health authorities, fears that there will be a third wave of swine flu after the first of the year, and he urged Californians to get vaccinated against it. “The majority of Californians remain susceptible” to the virus, he said, and vaccination is the best protection.
The state has received more than 12 million doses of swine flu vaccine, he said, and there is enough available now for anyone who wants it. “We can now recommend that all individuals seek vaccination,” he said.
Last week, there were 209 hospitalizations for confirmed swine flu cases, Horton said, down from 248 the previous week. Only 3% of visits to physicians’ offices were for complaints of influenza-like illness, down from 4% the preceding week.
But there were 32 laboratory-confirmed deaths from swine flu, compared with 20 the week before.
Since the beginning of the pandemic in April, California has seen 8,003 hospitalizations with laboratory-confirmed swine flu -- 1,600 of which required intensive care -- and 449 deaths. Of those hospitalized, 528 were pregnant women and 17 died, Horton said. “They have a higher death rate than other target groups,” he said. “There is no question they are disproportionately affected.”
The reasons for the high lethality of swine flu in pregnant women are not entirely clear, said Dr. Janice Louie, a medical and epidemiology section chief in the health department. Breathing can be impaired because of the fetus pushing against the lungs, exacerbating the effects of an infection, and pregnancy tends to lower the body’s immunity to infections.
Whatever the cause, it is also clear that pregnant women are often not receiving treatment soon enough -- in part because the rapid test for influenza frequently used in physicians’ offices gives a false negative 42% of the time, so physicians often do not start treatment as soon as they should, Louie said.
In a report Thursday in the New England Journal of Medicine, Louie and her colleagues reported on swine flu infections in 98 pregnant women and eight women who had just given birth during the first four months of the pandemic. Eight of the women died, and none of them had received antiviral drugs in the early stages of their disease. In six of the eight, rapid tests incorrectly indicated that the woman did not have swine flu. Pregnant women who did not receive antiviral drugs in the first two days of their infection were four times as likely to be placed in intensive care units, she said.
The message from the study, Louie said, is that pregnant women who have symptoms of the flu should be treated immediately with antiviral drugs to prevent the infection from progressing, even if a rapid test does not indicate swine flu.
If a follow-up genetic test indicates that she does not have swine flu, antiviral treatment can be stopped.
Times staff writer Rong-Gong Lin II contributed to this report.