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SESK: Stuff Everyone Should Know · sesk.info/dog-maternal-antibodies

Why do puppies need repeated vaccine doses until about 16 weeks old?

The mother's antibodies can block the vaccine.

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  1. The vaccine only lasts about a week
  2. Puppies only respond to vaccines in summer
  3. Antibodies from the mother can block the vaccine ✔

Why: Puppies get antibodies from their mother, and those can interfere with a vaccine. Nobody knows exactly when they fade for each puppy, so doses repeat until after 16 weeks.

Huh, didn't know that: AAHA says these antibodies may persist for 13 to 15 weeks or longer.

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References

Answer: Antibodies from the mother can block the vaccine. Puppies get antibodies from their mother, and those can interfere with a vaccine. Nobody knows exactly when they fade for each puppy, so doses repeat until after 16 weeks.

  1. AAHA, Key Vaccination: Canine Parvovirus (CPV) www.aaha.org/resources/2022-aaha-canine-vaccination-guidelines/canine-parvovirus-cpv
    MLV vaccines can be blocked by MDA against CPV
    Checked 2026-10-10.
  2. AAHA, Key Vaccination: Canine Parvovirus (CPV) www.aaha.org/resources/2022-aaha-canine-vaccination-guidelines/canine-parvovirus-cpv
    Revaccination is therefore recommended at 2 to 4 wk intervals until greater than 16 wk old.
    Checked 2026-10-10.

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