Figure 6.

Effects of prime/boost vaccination on clinical symptoms post‐challenge. Cotton rats were injected with PBS, immunized twice with 1 µg WIV, or were left untreated. Thirty days after the second immunization, immunized and mock‐immunized animals were challenged with 1 × 10⁷ TCID₅₀ of homologous virus, nontreated animals were again left untreated. After challenge, animals were followed for weight loss (A‐C), change in temperature (D‐F), and respiration rate (G‐I). Discontinued line with X symbol indicates dead animals. PBS, phosphate‐buffered saline; WIV, whole inactivated virus