He also pointed out other vaccines, such as the common polio vaccine used now, and the hepatitis A vaccine, show that a booster four to six months after the original shot provides a powerful and long-lasting increase in immunity.

他还指出，其他疫苗，如现在使用的普通脊髓灰质​​炎疫苗和甲型肝炎疫苗，表明在最初注射后四到六个月进行加强免疫可提供强大而持久的免疫力增强。