Table 5.

Feline leukemia virus vaccines.

Vaccine	Vector	Dosage	Price	Vaccination ages	Immune response	Protection	Ref.
Leucogen (Virbac, France)	p45 envelope antigen with adjuvant (aluminium hydroxide gel, extract of Quillaja saponaria)	Two initial doses at 3–4-week intervals injected im., annual revaccination with single dose	US$99.99/ten doses (US$9.99/dose)	8 weeks	Neutralizing antibodies within 9 weeks	80% preventable fraction against persistent viremia	[88]
Purevax®/ Eurifel (Merial Animal Health Ltd, UK)	Canarypox virus with env and gag genes and part of the pol gene of subgroup A (no adjuvant)	Two initial doses of 0.25 ml 3–4 weeks apart sc., annual revaccination with single dose	US$121.99/25 doses (US$4.88/ dose)	8 weeks	Cytotoxic T-cell response, very limited neutralizing antibody production	78% preventable fraction for persistent viremia	[89]
Leukocell 2 (Pfizer, NY, USA)	Inactivated, adjuvanted, mixed subunits from FeLV strains A, B and C, with sterile adjuvant	Two initial doses of 1 ml 3–4 weeks apart sc., annual revaccination with single dose	US$50.70/ten doses (US$5.07/dose)	9 weeks	Neutralizing antibodies within 7 weeks	Protects more than 70% of artificially immunosuppressed cats against persistent viremia	[90]
Fel-O-Vax LvK (Fort Dodge, KS, USA)	Inactivated whole virus of subgroups A and B with adjuvant	Two initial doses of 1 ml 3–4 weeks apart sc. or im., annual revaccination with single dose	US$74.00/ten doses (US$7.40/dose)	9 weeks	Neutralizing antibodies within 11 weeks	44–100% preventable fraction
Fevaxyn (Schering- Plough, NJ, USA)	Inactivated whole virus of subgroups A and B with adjuvant	Two initial doses of 1 ml 3–4 weeks apart sc., annual revaccination with single dose	US$119.99/25 doses (US$4.80/ dose)	9 weeks	Unknown	90.4–100% preventable fraction
DNA vaccine (Hanlon et al. 2001)	Two plasmids expressing gag/pol and env gene with adjuvant plasmids encoding feline IL-12, IL-18 and/or IFN-γ	100 µg of each DNA construct injected im.	Unknown	13–15 weeks	Unknown	100% protection against transient and persistent viremia, 5/6 kittens protected against latent infection	[18]

FeLV: Feline leukemia virus; im.: Intramuscular; sc.: Subcutaneous.