Frequently Asked Questions

Answers to some of the most frequently asked questions regarding Nobivac® Canine Flu H3N8 and canine influenza virus (CIV) infection.

When was Nobivac® Canine Flu H3N8 first approved in the US?
Merck Animal Health received a conditional license from the USDA for Canine Influenza Vaccine, H3N8 on May 27, 2009. After a year of safe use in half a million dogs, the USDA granted a full license on June 4, 2010. The vaccine is now known as Nobivac® Canine Flu H3N8.
How much protection does a dog get from the initial vaccine?
Nobivac® Canine Flu H3N8 is a killed virus vaccine. The initial vaccination primes the dog's immune response by stimulating the production of memory cells. If the dog were challenged after receiving a single dose, a memory response would ensue, leading to the production of antibodies, but the protection against the disease would not be as quickly achieved or as robust as it would be following a second vaccination. The second vaccination boosts the antibody production so that when challenged with natural canine influenza virus, the antibodies are ready to fend off the invading virus.
Is canine influenza virus (CIV) the same as canine parainfluenza (CPI) virus? If so, will the vaccines for each provide cross-protection?
Despite the similarity of their names, canine influenza virus (CIV) H3N8 are canine parainfluenza (CPI) virus are completely different viruses.
CPI is a common pathogen involved in canine upper respiratory infections, also known as kennel cough or canine cough. CPI infection causes only mild clinical signs, such as a mild hacking cough or a slight watery nasal discharge, but may become more severe if complicated by the presence of other viruses or bacteria. Local immune responses in the respiratory tract, such as immunity generated by the intranasal vaccines, are important for protection against CPI.
In contrast to CPI, CIV targets the lower respiratory tract and causes clinical signs ranging from mild to severe, including pneumonia and death. Since CIV is a new virus for dogs, virtually every dog exposed to it will become infected.
Vaccines for CIV and CPI do not provide cross-protection against each other. Therefore, separate vaccination against CIV is required to provide protection against the virus, particularly because dogs have no natural immunity to it, secondary bacterial infections are common, and viral shedding often decreases or stops prior to clinical signs.
Is canine influenza a seasonal disease?
No, it has and can occur in all seasons. However, increased incidence may be seen during periods when dogs are more likely to be placed in group environments, such as boarding facilities during summer vacations and seasonal holidays.
What precipitates the hemorrhagic form of the disease?
The hemorrhagic form of canine influenza is precipitated by individual susceptibility to the virus and secondary bacterial infections that exacerbate the pneumonia initiated by the virus. Bordetella bronchiseptica, Pasteurella spp., and Streptococcus spp. are known to attack the lung tissue already damaged by the virus.
What is the position of the AVMA on CIV?
According to a statement published by the organization on their website, “The AVMA believes there is an urgent need for an effective canine influenza virus vaccine to improve the health and welfare of animals and reduce the financial impacts of canine influenza.”19