Weight loss after Feline Core Vaccine in cats

The FDA has received 160 reports of weight loss in cats after Feline Core Vaccine. That is 10% of all reports for this medicine, compared with 4.6% across reports for all cat medicines, so it is reported unusually often with this medicine.

160Reports

67%Marked serious

24%Recovered

19%Died or euthanised

2 daysTypical onset

How soon it started

Same day

40 27%

1–2 days

35 23%

3–7 days

26 17%

1–4 weeks

36 24%

Over a month

12 8.1%

How the animals did

Recovered

39 24%

Still unwell when reported

66 41%

Died

16 10%

Euthanised

15 9.4%

Not known

24 15%

Problems reported at the same time

118 74%

105 66%

58 36%

58 36%

42 26%

29 18%

28 18%

27 17%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Type: vaccine.

Mild, short-lived lethargy, soreness or a small lump at the injection site are the most commonly reported vaccine reactions.

Questions owners ask

Can Feline Core Vaccine cause weight loss in cats?: 160 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 2 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Weight loss with similar medicines

Weight loss after Rabies Vaccine 208 reports · 8.0% of its reports
Weight loss after Feline Leukemia Vaccine 61 reports · 7.6% of its reports

All reported side effects of Feline Core Vaccine in cats · Medicines most reported with weight loss