What is the shortest interval at which Diphtheria, Tetanus, and Pertussis (DTaP) vaccine can be given?

From the Guidelines

The shortest interval at which the Diphtheria, Tetanus, and Pertussis (DTaP) vaccine can be given is 4 weeks (28 days) between doses. This minimum interval applies to the primary series, which consists of three doses typically given at 2 months, 4 months, and 6 months of age 1. If a child falls behind on the recommended schedule, catch-up vaccination can occur with this minimum 4-week spacing between doses to complete the primary series as quickly as possible. After the primary series, a fourth dose should be given at least 6 months after the third dose, typically at 15-18 months of age, and a fifth dose at 4-6 years 1. These minimum intervals are established to ensure adequate immune response development between doses while allowing flexibility for catch-up vaccination. Administering doses at intervals shorter than the recommended minimum may result in suboptimal immune response and might not be counted as valid doses, potentially requiring revaccination.

Some key points to consider:

• The primary series of DTaP vaccine consists of three doses, with a minimum interval of 4 weeks between doses 1.
• The fourth dose of DTaP should be given at least 6 months after the third dose, typically at 15-18 months of age 1.
• A fifth dose of DTaP is recommended at 4-6 years of age 1.
• The minimum interval between doses is crucial to ensure adequate immune response development and to allow for flexibility in catch-up vaccination 1.

It's worth noting that while the evidence from 1 discusses the use of Tdap vaccine in adolescents, the question specifically asks about the DTaP vaccine, which is used in younger children. Therefore, the recommendations from 1 are more relevant to this question.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

DTaP Vaccine Interval

The shortest interval at which the Diphtheria, Tetanus, and Pertussis (DTaP) vaccine can be given is not explicitly stated in the provided studies. However, the studies provide information on the typical schedule and flexibility of the DTaP vaccine administration:

• The Advisory Committee on Immunization Practices recommends administering DTaP vaccines to children at 2,4,6,15-18 months, and 4-6 years of age, preferably with the same-brand vaccine for the whole series 2.
• A study on the duration of protection after the first dose of acellular pertussis vaccine in infants found that the vaccine effectiveness (VE) of 1 and 2 doses of DTaP before 6 months of age and of 3 doses from 6 months of age was evaluated, but it does not provide information on the minimum interval between doses 3.
• Other studies focused on the immunogenicity and safety of combined DTaP-IPV vaccines compared to separate DTaP and IPV vaccines, but they do not address the shortest interval for DTaP vaccine administration 4, 5, 6.

Key Findings

• The typical schedule for DTaP vaccine administration is at 2,4,6,15-18 months, and 4-6 years of age 2.
• The vaccine effectiveness of DTaP vaccines wanes over time, especially without a booster dose 3.
• Combined DTaP-IPV vaccines have been shown to be safe and immunogenic when administered as pre-school booster doses 4, 5.

DTaP Vaccine Administration

• The studies do not provide a clear answer to the question of the shortest interval at which the DTaP vaccine can be given.
• However, they suggest that the typical schedule for DTaP vaccine administration should be followed, with flexibility in the administration of booster doses 2, 3, 4, 5, 6.