Influenza-Like Symptoms Being Reported in Large Numbers in Affected Areas
About 7% of the population in areas highly affected by H1N1 virus are reporting influenza-like symptoms, a spokesperson for the US Centers for Disease Control and Prevention (CDC) said during a press briefing today.
Daniel Jernigan, MD, MPH, deputy director of the Influenza Division at the National Center for Immunization and Respiratory Diseases at the CDC, provided an update about the H1N1 pandemic, stating that the United States will likely continue to have flu activity through this summer and probably until the start of the fall flu season.
According to Dr. Jernigan, approximately 89% of flu cases currently being confirmed by the CDC are of the novel H1N1 strain. The number of cases varies significantly from region to region, with northeastern states continuing to see the highest numbers, especially New York and Massachusetts.
Likely an Underestimate
The number of lab-confirmed cases in the United States is now estimated at more than 17,800, which includes around 1600 hospitalizations and 44 deaths.
“These numbers are likely an underestimate of the number of cases that are out there,” Dr. Jernigan said. “The amount of disease in the areas that are having activity with H1N1 is perhaps around 7% of the population reporting symptoms due to influenza-like illness.”
Antivirals — that is, neuraminidase inhibitors such as oseltamivir and zanamivir — still appear to be effective against H1N1. “We are recommending that [antivirals] be used in high-risk patients that are sick and also in those that are being hospitalized in those that have severe illness,” he said.
According to Dr. Jernigan, asthma, diabetes, and heart disease are the most predominant underlying conditions in hospitalized patients.
“About 70% or so [of hospitalized patients] have some kind of underlying disease,” Dr. Jernigan told Medscape Infectious Diseases during the call. “The most predominant [underlying condition] is asthma, [with] the second being diabetes.” He added that immunocompromised status — either through cancer chemotherapy or immunocompromising conditions — is present in about 13% of the patients, as is chronic underlying heart disease.
H1N1 in Healthcare Providers
H1N1 influenza infection among healthcare personnel was also discussed during the briefing. Michael Bell, MD, associate director for infection control in the Division of Healthcare and Quality Promotion of the CDC’s National Center for Preparedness, Detection, and Control of Infectious Diseases, discussed a report in the June 19 issue of the CDC’s Morbidity and Mortality Weekly Report.
The report, which describes H1N1 influenza cases among healthcare personnel detected up until May 13, 2009, includes detailed information about 26 patients. None of the patients with the H1N1 virus died or required intensive care during hospitalization, Dr. Bell said. Half of them had exposure within the general community or from unknown causes, and the remaining half probably contracted the disease within the healthcare setting.
According to the report, “most of the probable or possible patient-to-[healthcare provider] transmissions…occurred in situations where the use of [personal protective equipment] was not in accordance with CDC recommendations.”
Dr. Bell pointed out that they are beginning to see “a pattern of healthcare personnel to healthcare personnel transmission in some of these additional clusters, which is also concerning because it gets to the issue of people showing up for work sick.” He added that healthcare personnel should stay home if they are sick and that healthcare facilities need to have appropriate sick leave policies.
However, the report states that healthcare personnel do not appear to be “overrepresented among reported cases of persons infected with novel influenza A (H1N1) virus in the United States.”
According to Dr. Bell, there is currently no routine recommendation for healthcare workers to receive antiviral medication. “Probably the most important thing is that infectious patients be identified at the front door,” Dr. Bell said. “Consistent application of precaution is important to make sure that there isn’t occupational exposure.”
Current recommendations to prevent H1N1 spread include using a single patient room for infected individuals and having infectious patients cover their cough. Healthcare personnel are advised to use respirators, gloves, gowns, and eye protection while they are in patients’ rooms. In addition, careful attention to hand hygiene is also recommended.
CDC press briefing, June 18, 2009.