CDC explains why certain dogs must be revaccinated against rabies upon arrival in the US

Just over two weeks after its new requirements for dogs flying into the U.S. took effect, the U.S. Centers for Disease Control and Prevention is explaining why it's now requiring certain dogs that have already gotten a rabies shot to be revaccinated once they arrive in the U.S.

On Thursday, the federal agency said it's requiring foreign-vaccinated dogs to be revaccinated in the U.S. after an investigation identified certain rabies vaccines that are licensed abroad may not meet international vaccination production standards. Therefore, they might not provide sufficient protection in the nation's mission to prevent the reintroduction of the disease, which the U.S. has been free of since 2007, the CDC said .

This mission is why the CDC instated new import guidelines, effective Aug. 1, that differ depending on whether the pet is coming from a country with low or high rabies risk.

Dogs coming from low-risk countries must arrive with a CDC Dog Import Form , be at least 6 months old, have a microchip and appear healthy. In addition to those requirements, U.S.-vaccinated dogs coming from "high-risk" countries must have registered a certification of U.S.-issued rabies vaccination form or a USDA-issued health certificate.

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For foreign-vaccinated dogs coming from high-risk countries, the requirements include all those listed above plus a reservation at a CDC-registered facility for an examination and revaccination, in part, because of what the agency's investigation into potentially ineffective rabies vaccines revealed.

The CDC said in its report that it had been notified in mid-2021 of concerns about the Canvac R rabies vaccine's inefficacy. Around the same time, two dogs imported into Canada from Iran, one in July 2021 and one in January 2022, were diagnosed with rabies, despite receiving that vaccine.

Also in July 2021, a pandemic-era increase in dogs coming to the U.S. without adequate rabies vaccination records pushed the CDC to enact a temporary suspension of dogs coming from countries with a high risk of rabies — unless the dog's guardian applied for a CDC dog import permit, which identified vaccine product information.

Then in January 2022, after the second Canvac R-related rabies case, the CDC used the permits to identify 132 cases from Aug. 2021 to April 2024 in which dogs from 17 high-risk countries had been vaccinated with the potentially ineffective vaccine and then traveled to 28 U.S. states.

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Though the CDC dog import permit required revaccination, the CDC said compliance wasn't routinely confirmed, but after discovering the 132 Canvac R cases, it said it emailed the permit applicants to definitively confirm each dog had been revaccinated in the U.S.

Eight of the 132 told the CDC they didn't end up importing their dog to the U.S., while 102 provided proof of revaccination. The remaining 22 cases were referred to state and local health departments — and, in total, 94% of the dogs had received vaccinations.

Despite there being no signs of rabies in any of the dogs as of May 2024, the CDC says the investigation served as an example of its "best practices" for preventing the possible reintroduction of canine rabies in the U.S. and the reason why it requires foreign-vaccinated dogs to be revaccinated upon arrival in the U.S., regardless of which vaccine they have received abroad.