Recommendation: We recommend three more vaccinations with a combination vaccine that includes modified live parvovirus, distemper, canine adenovirus-2, and canine parainfluenza at every 3-4 weeks of age until 16 weeks of age. In addition, your puppy must be vaccinated for rabies after 16 weeks of age. Until recently, it was common practice to vaccinate also against leptospirosis and canine coronavirus. The UC Davis Veterinary School has recently informed veterinatians that coronavirus has been eliminated in the Western United States. The commercial leptospirosis vaccine only provides protection against one or two strains of the virus, and these have also been eliminated. There is a growing concern that we are overstimulating the immune systems of puppies by challenging them with so many different antigens in the same short period of time. With our own dogs, we do not vaccinate for leptospirosis or coronavirus. Our reasons for omitting these two vaccinations, which are still recommended by some vets are: 1. These pathogens are rare and apparently not present in the Western United States. 2. Although leptospirosis and coronavirus infections can be fairly serious, they are not often life-threatening, as is the case with parvo and distemper. 3. There is strong evidence that most allergic responses to vaccination are caused by the leptospirosis component.