While there have been only isolated cases of SARS since the 2003/2004 epidemic, it is likely that we will see future outbreaks. As a result, a number of laboratories are working on strategies for a SARS vaccine. One promising approach is being reported by Jan ter Meulen and colleagues.
The researchers developed a strategy called passive immunization, in which combinations of antibodies against the SARS virus are given to individuals at risk at the time of a possible new outbreak. Passive immunization strategies have been shown to curb outbreaks of hepatitis A virus and to prevent infection with varicella-zoster virus, and such antibody prophylaxis may be an effective means of controlling a future SARS outbreak.
To be effective, it is important that an antibody-based vaccine offers sufficient breadth of protection against all relevant strains of the SARS virus and prevents the selection of escape variants in the patient. In their study, the researchers present the characteristics of a combination of two human monoclonal antibodies that seem to have the desired characteristics in cell-culture experiments in the laboratory.