Breeding, Diseases, Parvo Info, Puppy and Kitten Care, Vaccines

Puppy Vaccination: Managing Parvovirus in a Litter or Kennel

It’s important to understand that parvovirus does not only affect puppies. Even adult dogs can have failure to respond to vaccinations. Up to 10 percent of dogs in our populations are thought to be “low responders” or “non-responders”. The only way to detect this condition is to do a titer blood test on each dog. These dogs that fail to respond to vaccinations can contract, become sick with, and even die of parvovirus as adults.

Puppy Vaccination Timing

Puppies who did not receive vaccines at the exact right time to provide active immunity while their passive immunity is declining.

As the passive immunity declines, there is a window of time between passive immunity dropping out and when a vaccination is administered and the puppy mounts an immune response. If there is exposure during this window, the pup(s) can contract parvovirus. This critical period can occur any time between six weeks of age and 20 weeks of age. Each litter reaches this critical period at a different time. Even the same dam’s litters will have different time ranges when they reach the critical period as her immunity will vary, based on her vaccination history and natural exposure to disease.


Puppies receive passive immunity from their mothers through colostrum, the first milk. Do your best to ensure the pups get plenty of colostrum at birth. Colostrum is only produced for a few days around the time when the pups are born. And puppies can only absorb colostrum for their first 12 hours after birth. Clearly, the production of colostrum and the ingestion and absorption is a delicately balanced process.

Puppies born by C-section before their dams are lactating, may not receive colostrum. If there are 14 puppies born, the 14th puppy may not receive colostrum – it is already depleted. If the dam passes away before her pups nurse, the pups won’t receive colostrum. What can you do if any of these three scenarios occur? Administer plasma or serum from an adult dog as a colostrum substitute. Plasma and serum are the fluid part of the blood, harvested after the red blood cells are removed. Fresh frozen plasma can be purchased, and stored frozen, from a canine blood bank. In the first 12 hours after birth, the plasma may be administered to the pups orally, using a feeding tube and syringe. After the first 12 hours after birth, plasma or serum may be administered by SQ, IV, or IO injection. After 12 hours post-partum, the pups will not be able to absorb these large antibody protein molecules through the gut.

So when is the passive immunity low enough that the puppy can respond to the vaccine? The answer to that is a great big fat – “it depends”.

There are three ways this can be managed.

    1. Blood test every puppy between four and six weeks of age to determine their titer. A titer is a test to assess antibody levels to a specific virus. Based on the titer, that drops off 50% every two weeks, we can calculate the correct time to start the vaccines. We don’t need to vaccinate multiple times – we can pinpoint the precise time a puppy will respond to his or her vaccination. This vaccination will create immunity IF the puppy responds normally, after only two doses.
    2. Blood test the dam each time she has a litter. Don’t draw the blood within two weeks of whelping as her titer will be artificially low. Based on this titer, a “nomogram” can be calculated. Assuming that all the pups in the litter receive an adequate amount of colostrum at a time they could absorb it, the date ranges the pups should receive their vaccinations can be calculated. This vaccination protocol will generally provide protective immunity using only two vaccine doses.
    3. Don’t do any testing. Make an informed best estimate at when pups will have diminishing antibody levels and be able to respond to vaccines. From research on thousands of dogs, we know their antibody levels drop below the blocking level sometime between six weeks and 20 weeks of age. As previously stated, not every puppy will have a diminished level at the same time. This is how most breeders and veterinarians make vaccination plans. Pediatricians do the same with young children – vaccinate on a predetermined schedule that works most of the time.When using this protocol, give boosters every two to four weeks, starting at six weeks of age and concluding at 20 weeks of age. Most puppies develop great immunity when vaccinated at 8, 12 and 16 weeks of age. Higher- risk puppies will benefit from vaccinating at 6, 9, 12, and 16 weeks of age.

Try to avoid vaccinating pregnant dogs and puppies under six weeks of age.

Do NOT vaccinate more frequently than every two weeks as this vaccination frequency will suppress the immune system.

Puppy Vaccine Reactions/Vaccine Mishandling

Unfortunately, there are puppies who do not tolerate vaccines well. There are a number of processes you can do to reduce the risk of puppy loss secondary to vaccinations.

    • Use only appropriate high-quality vaccines shipped and stored appropriately. Do NOT use vaccines that are expired or were not properly stored.
    • Administer the vaccine in the same location on each puppy, preferably over the shoulder, not in the scruff of the neck. Record the location.
    • Keep the vaccine vials or labels, showing the manufacturer, brand, lot, serial number, and expiration date of each vial.
    • Be certain to only vaccinate healthy pups, that have been appropriately dewormed, over six weeks of age and not more often than every two weeks. More isn’t better
    • Vaccinate puppies only when your veterinary clinic is open and available to help if your pups experience an adverse event.
    • After vaccination, observe the pups carefully for adverse events.
    • Have fluids you can give by subcutaneous injection available should your pups develop vomiting or diarrhea. This will help prevent dehydration.
    • Consider pre-medicating the puppies with baby aspirin and baby diphenhydramine (Benadryl) with the proper dose and advice of your veterinarian.

Should you lose a puppy shortly after vaccination, place the puppy in a plastic bag and refrigerate until you report the event and determine if the pup should be submitted for testing.

If you have more questions on puppy vaccination or the parvo vaccine, call us at 800.786.4751

Written by: Marty Greer, DVM

Director of Veterinary Services

Marty Greer, Doctor of Veterinary Medicine, has 40+ years’ experience in veterinary medicine, with special interests in canine reproduction and pediatrics. She received her Doctor of Veterinary Medicine from Iowa State University in 1981. She’s served as Revival’s Director of Veterinary Services since 2019. In 2023, Dr. Greer was named the Westminster Kennel Club Veterinarian of the Year.

If you need help, call us at 800.786.4751.