Pneumococcal Conjugate Vaccine Shortage
In December 2003, the Centers for Disease Control and Prevention (CDC) reported that Wyeth Vaccines, the only U.S. supplier of 7-valent pneumococcal conjugate vaccine (PCV7, marketed as Prevnar), was experiencing production constraints that could cause delays in shipments and was implementing an allocation plan to ensure the equitable distribution of available vaccine. However, production constraints have not been resolved and supplies will remain limited at least through July 2004. Until full production capacity is resumed, local shortages might occur. Effective immediately, the CDC recommends that physicians temporarily suspend routine use of the fourth dose of PCV7 to conserve vaccine and minimize the likelihood of shortages.
Preliminary data from the CDC’s Active Bacterial Core Surveillance program indicate that effectiveness, at least for the short term, is not compromised by delaying administration of the fourth dose. A case-control study comparing the effectiveness of a three-dose series with a four-dose series found that three doses were 90 percent effective against invasive disease caused by serotypes represented in the vaccine, whereas four doses were 96 percent effective; this difference is not statistically significant.
Because precise allocation of PCV7 is difficult, spot shortages are inevitable when supplies are limited. The CDC, in consultation with the American Academy of Family Physicians, the American Academy of Pediatrics, and the Advisory Committee on Immunization Practices, recommends that all physicians, regardless of the amount of PCV7 in their inventories, help conserve the national PCV7 supply by temporarily discontinuing administration of the fourth dose of PCV7 for healthy children. The recommendation was made to ensure that every child can be protected against pneumococcal disease despite the limited supply, and on the basis of the short-term effectiveness of the three-dose primary series of PCV7 at ages two, four, and six months. Physicians should continue to administer the fourth dose to children at increased risk for severe disease. Children whose booster dose is deferred should receive PCV7 on their first visit after supplies are restored.
Updated information about vaccine supplies is available athttp://www.cdc.gov/nip/news/shortages.
Recommendations for Avian Influenza A
The Centers for Disease Control and Prevention (CDC) has released interim recommendations for evaluating and reporting suspected cases of avian influenza A (H5N1). The recommendations are available online athttp://www.cdc.gov/mmwr/preview/mmwrhtml/mm5305a1.htm.
During December 2003 and February 2004, outbreaks of highly pathogenic avian influenza A among poultry were reported in Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam. As of February 9, 2004, 23 cases of laboratory-confirmed influenza A virus infections in humans, resulting in 18 deaths, had been reported in Thailand and Vietnam. In addition, approximately 100 suspected cases in humans are under investigation by national health authorities in Thailand and Vietnam. The CDC, World Health Organization, and national health authorities in Asian countries are working to assess and monitor the situation, provide epidemiologic and laboratory support, and assist with control efforts.
Antigenic analysis and genetic sequencing distinguish between influenza viruses that usually circulate among birds and those that usually circulate among humans. Sequencing of the H5N1 viruses obtained from five persons in Vietnam and Thailand, including one sister from the cluster in Vietnam, has indicated that all of the genes of these viruses are of avian origin. No evidence of genetic re-assortment between avian and human influenza viruses has been identified. If re-assortment occurs, the likelihood that the H5N1 virus can be transmitted more readily from person to person will increase. Although all the genes are of avian origin, the current H5N1 viruses are antigenically distinguishable from those isolated from humans in Hong Kong in 1997 and 2003.
Genetic sequencing of the five human H5N1 isolates from Thailand and Vietnam also indicates that the viruses have genetic characteristics associated with resistance to the influenza antiviral drugs amantadine and rimantadine. Antiviral susceptibility testing confirms this finding. Testing for susceptibility of the H5N1 isolates to the neuraminidase inhibitor oseltamivir has demonstrated the sensitivity of these viruses to the drug; testing to determine susceptibility to the neuraminidase inhibitor zanamavir is under way.
The CDC recommends that state and local health departments, hospitals, and physicians enhance their efforts to identify patients who could be infected by influenza A (H5N1) virus and take infection-control precautions when influenza A (H5N1) is suspected.
Testing of hospitalized patients for influenza A (H5N1) infection is indicated when both of the following exist: (1) radiographically confirmed pneumonia, acute respiratory distress syndrome, or other severe respiratory illness for which an alternative diagnosis has not been established, and (2) a history of travel within 10 days of symptom onset to a country where H5N1 avian influenza infections in poultry or humans has been documented. Ongoing listings of countries affected by avian influenza are available from the World Organization for Animal Health (available online athttp://www.oie.int/eng/en_index.htm).
Testing for influenza A (H5N1) also should be considered on a case-by-case basis in consultation with state and local health departments for hospitalized or ambulatory patients with all of the following conditions: (1) documented temperature higher than 38°C (100.4°F); (2) cough, sore throat, or shortness of breath; and (3) history of contact with poultry or domestic birds (e.g., visited a poultry farm, a household raising poultry, or a bird market) or a known or suspected patient with influenza A (H5N1) in an H5N1-affected country within 10 days of symptom onset.
The highly pathogenic avian influenza A (H5N1) virus requires Biosafety Level (BSL)-3+ laboratory conditions for certain procedures. The CDC recommends that virus isolation studies on respiratory specimens from patients who meet the testing criteria not be performed unless all BSL-3+ conditions are met. However, clinical specimens can be tested by polymerase chain reaction (PCR) assays by using standard BSL-2 work practices in a Class II biologic safety cabinet. The CDC has developed real-time PCR protocols (available to public health laboratories and online athttp://www.aphl.org) for various respiratory pathogens, including severe acute respiratory syndrome and influenza A and B viruses. In addition, commercially available antigen-detection tests can be used under BSL-2 levels to test for influenza. Although these rapid tests for human influenza also can detect avian influenza A (H5N1) viruses, the sensitivity of these tests is substantially lower than that of virus culture or PCR.
Specimens from persons meeting clinical and epidemiologic indications for testing should be sent to the CDC if these persons test positive for influenza A either by PCR or antigen-detection testing, or if PCR assays for influenza are not available locally. The CDC also will accept, for follow-up testing, specimens from persons meeting the clinical and epidemiologic indications but testing negative on the rapid tests when PCR assay was not available. Requests for testing by the CDC should come through local and state health departments, which should contact the CDC’s Emergency Operations Center at 770–488–7100.
The CDC advises that travelers to countries in Asia with documented H5N1 outbreaks avoid poultry farms, contact with animals in live food markets, and any surfaces that appear to be contaminated with feces from poultry or other animals. More information on travel is available online athttp://www.cdc.gov/travel. Information on influenza viruses and avian influenza is available online athttp://www.cdc.gov/flu.
Hormone Therapy Information for Women
The U.S. Food and Drug Administration (FDA) is asking manufacturers of hormone therapy products for postmenopausal women to include in their product labeling recent data from the Women’s Health Initiative Memory Study (WHIMS). The study found an increased risk of developing probable dementia in postmenopausal women 65 years of age or older during four years of treatment with oral conjugated estrogens plus medroxyprogesterone acetate compared with placebo. It is unknown whether this finding applies to younger postmenopausal women taking estrogen alone. The FDA emphasizes that although these findings are statistically significant, the risks to individual women are small.
The suggested updated labeling and a revised labeling guidance include information about current approved uses of the drugs: estrogen and combined estrogen with progestin products are effective for treating moderate to severe hot flushes and night sweats, moderate to severe vaginal dryness, and prevention of osteoporosis associated with menopause. The suggested label states that if these products are prescribed solely for vaginal symptoms, physicians are advised to consider the use of topical vaginal products. The suggested label recommends that if the products are prescribed for osteoporosis, women should be at significant risk for osteoporosis and non-estrogen treatments should be considered inappropriate.
The FDA also is advising women and their physicians that hormone therapy has never been approved for prevention of cognitive disorders such as Alzheimer’s disease or memory loss. In addition, the FDA is advising women to talk with their physicians, and if they decide that hormone therapy is appropriate, they should use the lowest effective dose for the shortest duration to reach treatment goals. Manufacturers must specify the lowest effective dose or state that the lowest dose of their drug has not been determined.
The results of the WHIMS study were published in the May 2003 issue of the Journal of the American Medical Association.
The FDA also is adding information from the Women’s Health Initiative study that found the use of estrogen with progestin may result in an increase in abnormal mammograms requiring further evaluation.
Additional information relating to hormone therapy is available online athttp://www.fda.gov/cder/drug/infopage/estrogens_progestins/default.htm.
Protective Eyewear for Young Athletes
The Eye Health and Public Information Task Force of the American Academy of Pediatrics’ Committee on Sports Medicine and Fitness has released a policy statement on protective eyewear. “Protective Eyewear for Young Athletes” appears in the March 2004 issue of Pediatrics and is available online athttp://pediatrics.aappublications.org. The policy statement has been endorsed by the American Academy of Ophthalmology.
More than 42,000 sports and recreation-related eye injuries were reported in 2000—most of those in people under age 25, and most associated with baseball and basketball. The recommendations include the following:
Protective eyewear is strongly recommended for all participants in sports in which there is a risk of eye injury. Polycarbonate is the most shatter-resistant clear-lens material, and should be used for all safety eye-wear. Also, young athletes should discard sports eye protectors that are damaged or yellowed with age.
Streetwear (fashion) spectacles are not satisfactory to wear for eye-injury risk sports. Athletes who wear contact lenses also should wear appropriate eye protection because contact lenses provide no eye protection.
All functionally one-eyed athletes should wear appropriate eye protection for all sports. In addition, functionally one-eyed athletes and those who have had an eye injury or surgery must not participate in boxing or full-contact martial arts. Wrestling has a low incidence of eye injury. However, wrestlers who have a custom-made eye protector must be aware that the protector design may be insufficient to prevent injury.
For sports in which a face mask or helmet with an eye protector or shield must be worn, it is strongly recommended that functionally one-eyed athletes also wear appropriate sports goggles to maintain some level of protection if the face guard is elevated or removed. The helmet must fit properly and have a chin strap for optimal protection.
Recommended sports-protective eyewear and American Society for Testing and Materials standards are reviewed in the policy statement. The task force notes that proper fit is essential, and provides recommendations for children who have narrow facial features and are unable to wear even the smallest sports goggles.