Equine Influenza Vaccination

Vaccination is the process to stimulate the body´s immune system to produce anti-bodies aiming to protect the body against infectious agents (Influenza virus), by injecting the body with antigens (infectious agents).

There are 2 types of immunization against infections as well as vaccination:

Passive immunization: In which the immune system produces anti-bodies in response to vaccination by injecting the body with an inactivated infectious agent (dead virus). This type of immunization is safe.

Active immunization: in which the immune system produces anti-bodies in response to an active infection and/or vaccination by injecting the body with a modified-live or active parts of the infectious agent. This type of immunization is solid and better.

There are 3 available forms of Equine influenza vaccines:

1- Inactivated vaccine (dead influenza virus)
2- Modified-live (MLV) vaccine (cold-adapted influenza virus)
3- Canary pox vector vaccine (the whole influenza virus or parts of it are carried on -a carrier- the canary pox virus)

1 and 3 are injected intra-muscular (i.m), while the MLV is given intranasal.

Vaccination schedule

The current available vaccine (Proteqflu) is a canary pox vector vaccine, which produces an active immunization through i.m injection. The other modified vaccine form is (Proteqflu-Te) in which the influenza virus is combined with Tetanus.

• Adult horses with no or irregular previous vaccination history should get the 3 dose vaccination schedule, in which the horse is injected the 1st dose, which is followed by the 1st booster dose after 3-4 weeks (one month), and then after 6 months from the date of the 1st booster dose the horse should get his 2nd booster dose.

The 1st injection dose and 1st booster dose, with one month interval are called Basic immunity or basic immunization.

For example:
01.01.2016: The horse has been injected his 1st vaccination dose.
01.02.2016: The horse should be injected his 1st booster dose.
01.08.2016: The horse must be injected his 2nd booster dose.

The next vaccination injection should be either each 6 months (according to FEI regulations) or every year (according to ECAHO regulations). Both are correct, but the FEI made these regulations because the horses are moving often worldwide in the same year, which predispose to a higher possibility of infection.

• Pregnant broodmares with previous regular vaccination history could be vaccinated 4-6 weeks before the delivery date, so that the foal can get Anti-bodies through colostrum (first milk after birth, which is rich with immune agents that help to protect the newly born foals against infections).

• Pregnant broodmares with no or irregular vaccination history should get 2 vaccination doses of the proteqflu vaccine (canary pox vector vaccine) but the 2nd dose must be 4-6 weeks before the delivery date, so the body can have enough time to produce anti-bodies and give it to the foal through colostrum.

For example:
Mare is due at 01.12.2016:
01.09.2016: The mare should be injected her 1st vaccination dose.
01.10.2016: The mare should be injected her 2nd vaccination dose. So this dose is 1-2 months before the delivery date.

• Foal of vaccinated mare should get their first vaccination schedule with 3 vaccination doses at the age of 6 months or after. Basic immunity, in which 1st vaccination dose followed by 1st booster dose in between one month (4 weeks) interval, and after 6 months of the 1st booster vaccination dose (2nd injection), foal must get the 2nd booster vaccination dose.

For example:
Foal was born at 01.01.2016:
01.07.2016: Foal should be injected his 1st vaccination dose.
01.08.2016: Foal must get his 1st booster vaccination dose.
01.02.2017 (after 6 months): Foal must be injected his 2nd booster vaccination dose.

Then regular vaccination schedule either each 6 months (according to FEI regulations) or every year (according to ECAHO regulations).

• Foals of no or irregular vaccination history of their mares should be watched till the age of 6 months. If they are healthy, they can start their vaccination schedule at the age of 6 months as mentioned above. However, if they are suffering from risk infectious situation, they might be vaccinated before the age of 6 months with 2 doses injections with 4 weeks interval in between, and 3rd injection after 6 months of the 2nd injection.