Clinical Capsules
Smallpox Vaccine
A cell-cultured smallpox vaccine can provide a safe and immunogenic alternative to the currently approved calf-lymph derived vaccine, a randomized controlled study suggests.
Of 350 vaccinia-naive and non-naive volunteers studied, 349 had evidence of successful immunization, reported Richard N. Greenberg, M.D., of the Veterans Affairs Medical Center in Lexington, Ky., and his colleagues. A total of 250 participants received equivalent doses of either the cell-cultured vaccine or the calf-lymph-derived vaccine (Dryvax), and the remaining 100 patients received the cell-cultured vaccine in varying dilutions. Adverse events and the extent of humoral and cellular immune responses were similar in the two vaccine groups, and the cell-cultured vaccine was effective at a dose 50 times lower than the dose of Dryvax (Lancet 2005;365:398-409).
The findings are important, because government organizations say more smallpox vaccine is needed, and because the manufacture of Dryvax—last produced in 1982—is unacceptable now. Poor controls in manufacturing leave it open to contamination with the infectious agent associated with the prion disease bovine spongiform encephalitis, the investigators explained.
SARS Recommendations
Another outbreak of severe acute respiratory syndrome is likely, and research is needed to better understand the etiology and to establish more specific treatment options, according to an expert panel convened by the National Heart, Lung, and Blood Institute, the Centers for Disease Control and Prevention, and the National Institute of Allergy and Infectious Diseases.
The multidisciplinary panel, convened to develop recommendations for treatment and study of respiratory failure associated with SARS, addressed topics such as the lack of proven value and need for study of antivirals, the importance of antibiotics in people with suspected SARS, the need for a lung-protective ventilatory strategy in patients with SARS that progresses to acute respiratory distress syndrome, and the need for a placebo-controlled trial of corticosteroids for SARS. The panel also addressed adjuvant treatments, noting the benefits of prophylaxis for deep venous thrombosis and stress ulcers (Am. J. Respir. Crit. Care Med. 2005;171:518-26).
An emergency clinical research infrastructure and development of a SARS patient registry are also needed, as is preparation for collection and storage of biological samples from patients, the panel concluded.
Pleural Infection Treatment
Intrapleural streptokinase was of no benefit in patients with pleural infection in a randomized, placebo-controlled trial.
In 427 patients who received either placebo or 25,000 IU of intrapleural streptokinase twice daily for 3 days, the proportion of patients who died or required drainage surgery at 3 months was similar in the two groups (27% of 221 in the placebo group and 31% of 206 in the streptokinase group). Median length of hospital stay was also similar in the two groups (12 and 13 days in the placebo and streptokinase groups, respectively), reported Nicholas A. Maskell, M.R.C.P., of Oxford Radcliffe Hospital, Headington (England), and his colleagues.
Outcomes, as measured with lung function tests and radiographs, also did not differ between the groups. However, those in the treatment group had significantly more serious adverse events, including chest pain, fever, and allergic reactions; 7% in the streptokinase group and 3% in the placebo group experienced such events, the investigators noted (N. Engl. J. Med. 2005;352:865-74).
Although intrapleural streptokinase is widely used in patients with pleural infection on the basis of small studies that showed some benefit, this larger, randomized trial suggests it should generally be avoided in these patients, the investigators concluded.
Infliximab and TB
Patients with infliximab-induced tuberculosis may be at increased risk of a paradoxical response to anti-tuberculous therapy, Carolina Garcia Videl, M.D, of the University of Barcelona (Spain) and her colleagues reported.
A retrospective analysis of 284 patients treated with infliximab showed that 6 developed tuberculosis during a 42-month observation period, and 4 of these had a paradoxical response to the anti-TB therapy—that is, they experienced otherwise unexplained clinical deterioration after initial improvement during the therapy(Clin. Infect. Dis. 2005;756-9).
Patients who experience this effect should remain on their anti-TB therapy for a prolonged period of 9-12 months, and may respond to early addition of corticosteroids to the treatment regimen, they said.
