Chapter 3: Vaccination

Vaccination is the cornerstone of parvovirus prevention in shelters and communities. In the absence of maternal antibody interference, a single modified live vaccine can confer protection within 3-5 days.¹ Research to date has found that currently available vaccines protect against all known strains of parvovirus, including parvovirus 2c.^2,3 All dogs and puppies > 4 weeks of age should be vaccinated at the time of shelter admission (or ideally, at least a week before), including those who are injured or mildly ill.(In shelters where parvo is extremely rare, vaccination may be started at 6 weeks instead of 4 weeks.)  Revaccinate puppies every two weeks until 18-20 weeks of age⁴ as long as they remain in the shelter, and consider revaccinating adult dogs at least once 2 weeks after the first vaccine or after adoption.

For pregnant dogs, the risk of parvovirus infection must be balanced against the risk of vaccine-induced abortion. If the decision is made not to vaccinate a pregnant dog, titers should ideally be performed to evaluate susceptibility to infection (see below) and these dogs must be carefully mechanically isolated unless confirmed to have an adequate titer. Because maternal antibody can interfere with vaccination in puppies under 16 weeks, they also need to be mechanically protected from exposure by ensuring that they are housed in easily cleaned and disinfected areas; handled and cared for by people with clean hands, shoes, and clothes; and ideally, removed from the shelter to foster care, adoption or rescue as quickly as possible.

CPV enters and spread in shelters from dogs infected in the surrounding community. A cost effective and humane strategy for long term control is to ensure that community members have ready access to affordable vaccines for their pets.