Background During systemic lupus erythematosus (SLE), infections are often more severe, and may cause disease flares. Pneumococcal and influenza vaccines are therefore recommended for SLE patients, but their immunogenicity and tolerability in this particular context is still debated.

Objectives To assess the immunogenicity and the impact on lupus activity of pneumococcal and influenza vaccines in SLE patients.

Methods We conducted a systematic literature review in Medline, Scopus, Cochrane databases and abstracts from the ACR and EULAR congresses. To be considered for inclusion, studies had to compare the response of either pneumococcal or influenza vaccines between SLE patients and healthy controls. Humoral response against pneumococcal serotype 23F and AH1N1, AH3N2 and B influenza strains had to be assessed either by a seroconversion (SC) rate or a seroprotection (SP) rate between three and six weeks after vaccination. Impact on disease activity assessed by the Systemic Lupus Erythematosus Disease Activity Index score (SLEDAI) was evaluated by the comparison of SLEDAI score before and three to eight weeks after vaccination. Odds-ratios (OR), relative risks (RR) and their 95% confidence intervals (95% CI) were pooled using the generic inverse variance method. Heterogeneity between studies was assessed using the chi-square Cochran Q-test and the I² statistic. RevMan software 5.1 version was used for all analysis. A significant statistical threshold of 0.05 was used.

Results Out of 47 potentially relevant studies, only 20 were included, 3 for pneumococcal vaccine, gathering 67 patients and 26 healthy controls and 17 for influenza vaccine, gathering 1598 patients and 800 healthy controls. For pneumococcal vaccination, no significant difference was observed for SC rate one month after vaccination between SLE patients and controls (pooled RR=0.97; 95% CI (0.63-1.50); p=0.89, I²=35%). The SLEDAI score before vaccination was not significantly modified after vaccination (pooled Mean difference=0.29; 95% CI (-0.90-1.48); p=0.63, I²=0%). For influenza vaccination, the response against AH1N1 strains was significantly reduced in SLE patients, with a lower rate of SC (pooled OR=0.38; 95% CI (0.27-0.54); p<0.00001, I²=39%) and SP (pooled OR=0.36; 95% CI (0.28-0.47); p<0.00001, I²=25%). For AH3N2 strain, only SP rate was significantly lower in SLE patients (pooled OR=0.26; 95% CI (0.14-0.50); p<0.0001, I²=21%) but not SC rate. For B strain, neither SC rate nor SP rate were significantly different. The SLEDAI score before vaccination was slightly decreased after vaccination (pooled Mean difference=0.60; 95% CI (0.09-1.11); p=0.02, I²=32%).

Conclusions The immunogenicity of pneumococcal vaccination seems to be preserved in SLE patients whereas the immunogenicity to influenza vaccine depends on the viral strains. In this population, vaccine against AH1N1 strain seems to be less immunogenic than vaccine against AH3N2 and B strains. Analysis of the possible factors modulating the vaccinal response could not be performed in this study.

Disclosure of Interest None declared