Which of the following vaccines is recommended for all children younger than 2 years?

The recommended vaccine for all children younger than 2 years is PCV13, which stands for Pneumococcal Conjugate Vaccine 13-valent. This vaccine is crucial because it protects against infections caused by the bacteria Streptococcus pneumoniae, which can lead to serious conditions such as pneumonia, meningitis, and blood infections in young children.

The vaccine is part of the routine immunization schedule for infants and is usually given in a series starting at 2 months of age, with subsequent doses at 4 months, 6 months, and a final booster at 12 to 15 months. Ensuring that children receive this vaccine before the age of 2 helps to build immunity during a critical period of their development when they are particularly vulnerable to these serious infections.

Other vaccines listed, such as TDAP, PPSV23, and Shingrix, are either recommended for different age groups or specific populations rather than universally for all children under 2 years. For example, TDAP is typically recommended for older children and adults, PPSV23 is often used for older adults and those with certain health conditions, and Shingrix is designated for adults over 50 years of age to prevent shingles.