A 4-year-old boy is brought to the physician for a 12-hour history of worsening respiratory distress. His family immigrated to the US from China 2 years ago. Physical examination shows drooling, tripod positioning, and use of accessory muscles. X-ray of the neck shows a thumbprint sign. Which of the following vaccine types is most likely to have prevented this patient’s condition?
Conjugate
Killed-intramuscular
Live-attenuated
Polysaccharide
Toxoid
