Right, but if you just got the primary exposure, wouldn't the secondary response automatically-- not a booster shot, just the secondary response, because you were exposed?

但这时你已经获得这样的初次免疫,而因为你已经天然感染过该病毒,那么,在没有加强针的情况下,二次免疫是否无法自动发生

耶鲁公开课 - 生物医学工程探索课程节选

Investors are getting a big booster shot of income to a portfolio without having to compromise credit quality.

FORBES: Magazine Article

In 2005, a booster shot called Tdap was introduced for adolescents and adults that inoculates against tetanus, diphtheria and pertussis.

CNN: Vaccination role unclear in whooping cough outbreak

The outbreak lead to a requirement that at age 10, before entering the seventh grade, kids must have a Pertussis booster shot.

CNN: Opting out of vaccinations could get tougher in California