Jan 8, 2004 (CIDRAP News) The 2003-2004 influenza season may already be past its peak, but it has claimed the lives of 93 children, the Centers for Disease Control and Prevention (CDC) reported today.
Flu activity was widespread in 38 states during the week ending Jan 3, down from 42 states in the week ending Dec 27, the CDC reported. Nine states had regional activity and the other states had lower levels or didn't report. The number of states with widespread activity had reached 45 in the week that ended Dec 20.
"We are cautiously optimistic that at least in some parts of the country influenza may have peaked" for this year, CDC Director Dr. Julie Gerberding said during a news briefing this afternoon. But she warned that the flu could have a second surge, perhaps with a different viral strain, as it has in some years.
Preliminary data from 31 states show that 93 children have died of influenza-related causes since October 2003, the CDC reported in the Jan 9 issue of Morbidity and Mortality Weekly Report. All had laboratory evidence of flu infection.
The toll cannot be directly compared with previous flu seasons, because reporting of confirmed flu cases and related deaths in children is not legally required, the CDC said. But Gerberding said the agency has asked the Council of State and Territorial Epidemiologists to consider taking steps to change that. "I'm fairly optimistic that we'll see some changes in the reporting to make this a more standardized methodology," she said. Meanwhile, the CDC has asked state and local health departments to report all flu-related deaths in children younger than 18.
The children who died ranged in age from 4 weeks to 17 years, with a median of 4 years. Thirty-five of the 93 had a chronic underlying medical condition, while 41 had no underlying condition and the medical history was unknown for 17. Mental retardation or developmental delay, reported in 12 children, was the most common chronic condition.
Of the 45 children whose flu vaccination status was known, 1 had been fully vaccinated, 33 had not been vaccinated, and 6 had had one of two doses. The other five children reportedly were vaccinated, but the time between vaccination and onset of illness was not known. (Flu vaccine takes about 2 weeks to reach peak effectiveness.)
Twenty-five of the 93 children had pneumonia as a flu complication, according to the report. Fifteen children had "invasive bacterial co-infections," involving such species as methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Enterococcus species, Haemophilus influenzae (type b and non-typeable), and Neisseria meningitidis.
In data from 122 cities, the proportion of deaths attributed to pneumonia and influenza was 9.0% the week of Dec 21-27 and 9.4% the week of Dec 28 through Jan 3. The number surpassed the epidemic thresholds of 7.9% and 8.0% for the 2 weeks.
The percentage of visits to sentinel medical providers for treatment of influenza-like illnesses reached 8.8% during the week ending Dec 27 (compared with 7.7% the previous week) but dropped to 6.2% the week ending Jan 2, the CDC reported.
The Fujian subtype of influenza A (H3N2) continued to be the predominant virus strain among isolates analyzed by the CDC. Nearly all the isolates analyzed were influenza A (H3N2), and 78.4% of those were Fujian, with the Panama subtype accounting for the rest.
CDC officials voiced concern earlier in the season that this year's flu vaccine might not provide full protection against the Fujian strain, which emerged too late to be incorporated in the vaccine. Officials did not offer an assessment of the vaccine's effectiveness today.
Shortages of flu vaccine were reported in many parts of the country in December. In response to a question about the vaccine supply today, Gerberding gave little information. She said that plenty of FluMist, the intranasal vaccine for healthy people aged 5 to 49 years, is still available. The CDC has distributed some of the extra doses of conventional vaccine it procured from Chiron Inc., but some jurisdictions have not ordered any of that vaccine, she added.
In other comments today, Gerberding said the one confirmed and one suspected case of SARS (severe acute respiratory syndrome) in China do not warrant any travel advisories at this point. She praised the containment and surveillance steps China has taken and said the CDC has sent a SARS expert to China to help investigate the source of the infections there.
Referring to the current culling of civets from animal markets in southern China because they may carry a SARS-like virus, Gerberding said, "Right now there's no scientific evidence proving that these animals are the source of SARS." The civets may carry a coronavirus, but it is not identical to the SARS coronavirus, she said.
Jan 9 MMWR report on flu deaths in children
Jan 9 MMWR report on flu activity from Dec 21, 2003, through Jan 3, 2004
CDC flu summary for week ending Dec 20, 2003