Flu Vaccine Coverage
Efforts to direct influenza vaccine to priority groups during the 2004–2005 vaccine shortage were “somewhat” successful, according to the Centers for Disease Control and Prevention.
Vaccination coverage for all groups nationwide in 2004–2005 declined 46% from the 2003–2004 period, with the greatest decreases in younger people (51% in those aged 50–54 vs. 41% in those aged 60–64) and in people with self-reported good health; coverage dropped 52% in those with “excellent” health, 35% in those with “fair” health, and 24% in those with “poor” health.
The findings were based on an analysis of data that were sampled from the 70 million members of the 250 managed care organizations in the Consumer Assessment of Health Plans survey (MMWR 2005;54:921–3).
The substantial decreases observed in vaccination coverage among those with fair or poor health in this population are of concern.
Research regarding medical conditions associated with self-reporting of fair or poor health could help develop tools for managing future vaccine shortages, the CDC noted.
Flu Vaccine Efficacy
Elderly patients in long-term care facilities appear to get the most benefit from flu vaccination, whereas those in the community receive only modest benefits, Tom Jefferson, FFPHM, of the Cochrane Vaccines Field in Allesandria, Italy, and his colleagues reported.
The investigators reviewed data from 64 studies of influenza vaccine effectiveness and found that the effectiveness of well-matched vaccines in areas with high viral circulation was 23% against flulike illness. Such vaccines in this setting were not significantly effective against influenza, but vaccine effectiveness (VE) was 46% for preventing pneumonia, 45% for preventing hospital admission for influenza and pneumonia, 42% for preventing death associated with influenza or pneumonia, and 60% for reducing all-cause mortality (Lancet 2005;366:1165–74).
In elderly people living in the community, well-matched vaccines were not significantly effective against influenza, influenza-like illness, or pneumonia, but adjusted VE was 26% for preventing death from influenza and pneumonia, 29% for preventing hospital admissions for all respiratory illnesses, and 47% for reducing all-cause mortality.
Efforts should concentrate on increasing vaccination coverage in long-term care facilities, on assessing the effect of vaccination in high-risk groups, and on developing better vaccines by incorporating improved knowledge of influenza-like illnesses in different communities, the investigators concluded.
Flu Vaccine Development
The National Institute of Allergy and Infectious Diseases and MedImmune Inc. together will develop vaccines against avian influenza viruses that could cause pandemics, according to the Department of Health and Human Services.
The agreement was prompted by concerns that the viruses could acquire the ability to spread efficiently from person to person and cause a global outbreak.
The two organizations will develop at least one vaccine for each of 16 variations of hemagglutinin, a key influenza surface protein. One priority is development of a vaccine against the H5N1 virus, which has spread rapidly among birds and other animals in Asia over the past 2 years and has affected at least 115 people throughout Asia. The collaborative effort could take years, but will help in preparing for future influenza pandemics, the HHS stated.
Oyster-Related Gastroenteritis
An outbreak of Vibrio parahaemolyticus infection linked with Alaskan oysters has extended the northernmost documented source of such oyster-related illness by 1,000 km.
Rising ocean water temperatures appear to have contributed to the outbreak, which occurred among cruise ship passengers, Joseph B. McLaughlin, M.D., of the Alaska Department of Health and Social Services and his colleagues reported.
A retrospective cohort study of 132 passengers showed that raw-oyster consumption was the only significant predictor of illness (adjusted odds ratio 5.2). An environmental analysis showed that most of the oysters associated with the outbreak were harvested from a single farm with mean daily water temperatures frequently over 15.0° C during July and August harvesting. This temperature is believed to be the threshold for the risk of V. parahaemolyticus infection (N. Engl. J. Med. 2005;353:1463–70).
Control measures, including monitoring for V. parahaemolyticus, should be considered when water temperatures at oyster farms exceed 15° C, the investigators said.
Sharon Worcester