Porcine reproductive and respiratory syndrome virus vaccines: Immunogenicity, efficacy and safety aspects

Table 1 Porcine reproductive and respiratory syndrome virus genome and relevant information

ORF	Product	Function	Role in immunity/protection	Ref.
1a	Nsp1α	Papain-like cysteine protease	Potential IFN and TNFα antagonist	[66-68]
	Nsp1β	Papain-like cysteine protease	Potential IFN and TNFα antagonist	[66,68,69]
	Nsp2	Cysteine protease	Potential IFN antagonist	[70]
	Nsp3	Transmembrane protein	NA	[70]
	Nsp4	Serine protease	NA	[70]
	Nsp5	Transmembrane protein	NA	[70]
	Nsp6	NA	NA	[70]
	Nsp7α	NA	Potential antigen for serological determination of persistence infection	[70]
	Nsp7β	NA	Potential antigen for serological determination of persistence infection	[70]
	Nsp8	NA	NA	[70]
1b	Nsp9	RNA-dependent RNA polymerase	NA	[70]
	Nsp10	Helicase	NA	[70]
	Nsp11	Endoribonuclease	Potential IFN antagonist	[70,71]
	Nsp12	NA	NA	[70]
2a	GP2	Minor envelope protein; interacts with CD163	Minor neutralizing epitope	[72]
2b	E protein	Minor envelope protein; possibly form oligomeric ion channel	NA	[72]
3	GP3	Minor envelope protein	Minor neutralizing epitope	[72]
4	GP4	Minor envelope protein; interacts with CD163	Minor neutralizing epitope	[72]
5	GP5	Major envelope protein; interacts with sialoadhesin	Major neutralizing epitope	[72]
6	M protein	Major envelope protein; interacts with heparan sulfate	T cell epitope; minor neutralizing epitope	[72]
7	N protein	Nucleocapsid	Non-neutralizing epitope	[72]

Nsp: Non-structural protein; GP: Glycoprotein; NA: No data available; ORF: Open-reading frames.

Table 2 Recommendation and vaccination schedule of commercial PRRS modified-live virus vaccines

Vaccine1	Pigs2	Route	Dose (mL)	Program
Ingelvac PRRS MLV	Gilt/Sow	im	2	At any stage of production3
	Piglet/Nursery/Growing	im	2	At any stage of production3
ReproCyc PRRS-PLE	Gilt/Sow	im	5	Primary: 4-6 wk prior to breeding
				Booster: prior to subsequent breeding
Ingelvac PRRS ATP	Nursery/Growing	im	2	At 3-18 wk of age
Porcilis PRRS	Gilt/Sow	im/id	2/0.2	Primary: 2-4 wk prior to breeding
				Booster: 2-4 wk prior to subsequent breeding/or every 4 mo
				At 2 wk of age or older
	Piglet/Nursery/Growing	im/id	2/0.2
Amervac-PRRS	Nursery/Growing	im	2	At 4 wk of age or older
Pyrsvac-183	Gilt/Sow	im	2	Primary: 2-4 wk prior to breeding
				Booster: 3-4 wk prior to subsequent breeding
	Piglet/Nursery/Growing	im	2	At 2-3 wk of age or older

¹Not recommended for use in porcine reproductive and respiratory syndrome virus-negative farms;

²Not recommended for use in boars due to negative impact on semen quality[73];

³Recommended to revaccinate every 3-4 mo for whole herd vaccination program. im: Intramuscularly; id: Intradermally.

Table 3 Recommendation and vaccination schedule of commercial PRRS killed virus vaccines

Vaccine	Pigs	Route	Dose (mL)	Program
Progressis/	Gilt	im	2	Primary: twice, 3-4 wk interval, at least 3 wk prior to breeding
Ingelvac PRRS KV				Booster: 60-70 d of each gestation
	Sow			Primary: twice, 3-4 wk interval, at any stage of production
		im	2	Booster: 60-70 d of each gestation
Suipravac-PRRS	Gilt	im	2	Primary: twice, 3-4 wk interval, when entering the farm
				Booster: Follow sows’ vaccination program
	Sow	im	2	Primary: twice, 3-4 wk interval, during pregnancy or lactation
				Booster: every 4 mo
Suivac PRRS-INe/Suivac PRRS-IN	Gilt/Sow	im	2	Primary: three times; 1st at 5-6 mo of age, 2nd at 3-4 wk after 1st, and 3rd at 6-4 wk prior to expected farrowing
				Booster: twice; 1st at 3-4 wk after the farrowing, and 2nd at 6-4 wk prior to the further expected farrowing
	Boar	im	2	Primary: twice, 4 wk interval, starting at 6 mo of age
				Booster: every 4-6 mo
	Nursery/Growing	im	2	Three times: 3-4 wk interval, starting at 6-10 wk of age

im: Intramuscularly; KV: Killed virus.

Table 4 Alternative PRRS vaccines

	Encoded ORF/GP	Immunogenicity		Protection		Ref.
		Antibody	CMI	Homologous	Heterologous
DNA vaccine	ORF1-7	+	+	+	ND	[45,46]
Subunit vaccine	GP5	Poor	Poor	-	ND	[47,48]
Synthetic peptide vaccine	GP5	-	-	ND	-	[13]
Adenovirus vector vaccine	GP3, 4, 5	+	+	ND	ND	[49-51]
PRV vector vaccine	GP5, M	+	+	+	ND	[52,53]
Poxvirus vector vaccine	GP3, 5, M	+	+	+	ND	[54,55]
TGEV vector vaccine	GP5, M	+	ND	+	ND	[56]
Alphavirus-derived replicon	GP5, M	+	+	+	+	[57]
Bacterial vector vaccine	GP5, M	+	-	+	ND	[58]
Insect cell-derived vaccine	ORF3, 5, 7	+	ND	+	ND	[59]
Plant-derived vaccine	GP5	+	+	ND	ND	[60,61]
Gene-deleted MLV (deleted15-mer nsp2 epitope)		+	ND	ND	ND	[65]

+: Success; -: Failure; ND: Not determined.