Which statement about canine vaccination is true?

• A. Vaccines provide complete lifelong immunity without boosters
• B. Boosters required; maternal antibodies can interfere with early vaccines
• C. Vaccination status does not affect disease risk
• D. Vaccines are contraindicated in puppies under 8 weeks

Answer: (B)

The idea being tested is how canine immune protection is built over time with vaccination and why boosters are needed. Maternal antibodies passed from the dam can neutralize vaccines given early, keeping the puppy’s own immune system from responding. As these maternal antibodies wane, later vaccine doses are needed to stimulate active immunity and maintain protection. Because the timing of antibody decline varies among puppies, a series of vaccines (boosters) is used to ensure the puppy becomes and remains protected. In practice, vaccination typically starts around 6–8 weeks and is repeated every 3–4 weeks until about 16 weeks, with a booster at around one year and then at risk-based intervals.

Other statements aren’t accurate: a single vaccine dose does not provide complete lifelong immunity; immunity can wane and require boosters. Vaccination status does affect disease risk—unvaccinated or under-vaccinated dogs are more at risk. Vaccines are not universally contraindicated in puppies under 8 weeks, since some vaccines can be given starting at about 6 weeks depending on the vaccine and protocol.