預防

to prevent / to take precautions against / to protect / to guard against / precautionary / prophylactic

to advance / in advance / beforehand / to prepare

to protect / to defend / to guard against / to prevent

immunization injection / fig. forewarning / heads-up / preventive measure

prophylactic inoculation

prophylactic / preventative / protective

prophylactic inoculation

Center for Disease Control (US)

protective step / protective measure

prophylaxis / medical prevention