Is there hope for the prevention of future antimicrobial shortages?

postexposure rabies vaccination in patients with human immunodeficiency virus with low CD4 ϩ T lymphocyte cell counts. Reply Sir—We thank Drs. Mary and David War-rell [1] for noting the error in the percentage of patients with seroconversion presented in table 2 of our article [2]; the rate should have appeared as 27%, not 7%. On day 7 of the regimens, the levels of neutralizing antibodies (NAbs) in all patient groups ranged from undetectable to 0.4 IU/mL (geometric mean titer [GMT], 0.04 IU/mL) [3]. This titer is 10 times less than the lowest acceptable titer (0.5 IU/mL) recommended by the World Health Organization (WHO) [4, 5]. compared levels of NAbs in patients on days 0, 5, 7, and 14 of each of the 4 reg-imens followed. The regimens included the Essen regimen, the Thai Red Cross regimen (TRC-ID), the Oxford 8-site reg-imen, and the " double-dose " TRC-ID (for dosages, see [2]). On day 5 of the regi-mens, NAb levels were undetectable. On day 7 of the regimens, the GMT was only 0.13 IU/mL (range, 0.03–0.5 IU/mL) in the group receiving the 8-site intradermal regimen. We suggest that these NAb levels are unlikely to intercept the virus before it enters the peripheral nerves [6]. If rabies immunoglobulin (RIG) was unavailable, use of the 8-site regimen was recommended by the WHO, but they cited no scientific evidence to support this recommendation [4]. We had reservations when Briggs et al. [7] performed a study in which only 0.1 mL of vaccine was used per injection site, rather than the WHO-recommended dose of 0.2 mL of vaccine from 1.0 mL of reconstituted purified chick embryo vaccine [7]. TRC-ID was developed for the use of purified Vero cell vaccine that is reconstituted in 0.5 mL of saline. Both vaccines have approximately equivalent antigen contents (6–14 IU), amounts that are several times greater than the WHO-recommended level of 2.5 IU. Briggs et al. [7], nevertheless, demonstrated that their vaccine regimen had good immunogen-icity. This led to early application of TRC-ID with 0.1 mL of purified chick embryo vaccine per intradermal dose. There were no treatment failures among 7227 patients treated in a province in which canine rabies was endemic [8]. Only 216 (3%) of these 7227 patients also received RIG. Unlike the Warrells, we are not aware of any confusion about these issues in Thailand. This country used TRC-ID for 5 years before it became the …