Search

Objectives To compare the homologous prime-boost vaccination scheme of Gam-COVID-Vac (Sputnik V (SpV)) to its heterologous combination with mRNA-1273 (Moderna (Mod)) vaccine. Methods SARS-CoV-2 anti-spike (S)-receptor binding domain (RBD) IgG concentration was assessed three to seven weeks after complete vaccination. Reactogenicity was evaluated by declared side events and medical assistance required until day 7 post boost. Results Of 190 participants enrolled, 105 received homologous SpV/SpV and the remaining heterologous SpV/Mod vaccination scheme, respectively. Median (interquartile range (IQR)) age was 54 (37–63) years, 132 out of 190 (69.5%) were female, and 46 out of 190 (24.2%) individuals had a prior confirmed COVID-19. Anti-S-RBD IgG median (IQR) titers were significantly higher for SpV/Mod (2511 (1476–3992) binding antibody units (BAU)/mL) than for SpV/SpV (582 (209–1609) BAU/mL; p < 0.001] vaccination scheme. In a linear model adjusted for age, gender, time to the serological assay, and time between doses, SpV/Mod (4.154 (6.585–615.554); p < 0.001] and prior COVID (3.732 (8.641–202.010); p < 0.001) were independently associated with higher anti-S-RBD IgG values. A higher frequency of mild and moderate adverse effects was associated with the heterologous scheme (20 of 85 (23.5%) vs. 13 of 105 (12.4%); p = 0.043 and 27 of 85 (31.8%) vs. 14 of 105 (13.3%); p = 0.002), respectively, although it was well tolerated by all individuals and no medical assistance was required. Discussion The heterologous SpV/Mod combination against SARS-CoV-2 is well tolerated and significantly increases humoral immune response as compared to the homologous SpV/SpV immunization.

We appreciate the observation from the authors Rujittika Mungmunpuntipantip and Viroj Wiwanitkit [1] regarding our publication [2]. Certainly, there is a vast number of factors that may affect immunological parameters from a greater to a lesser extent. We agree this is an important aspect, so the analysis of the immunological parameters assessed in our work has considered the broadly established factors that may have potentially impacted the immune response in our setting. Although elevated anti-S-RBD immunoglobulin (IgG) values after asymptomatic COVID-19 cannot be excluded, both groups of our comparative study would have been affected similarly; therefore, an impact on the conclusions would unlikely be altered. Moreover, the detection of the nucleoprotein IgG antibody to distinguish vaccine-induced seropositivity from natural infection is limited due to its significant decrease after 120 days postinfection period [3]. Consequently, we felt that the analytical approach initially performed in our research was accurate. Finally, the immune response variations according to different boost vaccination schemes observed in our study were also registered in a subset of patients receiving dialysis [4] and confirmed by a recently published study that assessed the humoral response to several vaccination schemes, including the homologous prime-boost vaccination with Gam-COVID-Vac and the heterologous combination with mRNA-1273 (Moderna) vaccine [5].

Introduction Growing data are demonstrating safety and immunogenicity of heterologous vaccination schemes against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. This strategy opens up the possibility of a shorter path towards the end of the pandemic. Objective To compare the homologous prime-boost vaccination scheme of Gam-COVID-Vac (Sputnik V, SpV) to its heterologous combination with mRNA-1273 (Moderna, Mod) vaccine. Methods SARS-CoV-2 anti-spike (S)-receptor binding domain (RBD) IgG concentration was assessed three to seven weeks after complete vaccination. Reactogenicity was evaluated by declared side events and medical assistance required until day 7 post-boost. Results Of 190 participants enrolled, 105 received homologous SpV/SpV and the remaining heterologous SpV/Mod vaccination scheme, respectively. Median (interquartile range, IQR) age was 54 (37-63) years, 132 (69.5%) were female and 46 (24.2%) individuals had a prior confirmed COVID-19. Anti-S-RBD IgG median (IQR) titers were significantly higher for SpV/Mod [2511 (1476-3992) BAU/mL] than for SpV/SpV [582 (209-1609) BAU/mL, p<0.001] vaccination scheme. In a linear model adjusted for age, gender, time to the serological assay and time between doses, SpV/Mod [4.154 (6.585-615.554), p<0.001] and prior COVID [3.732 (8.641-202.010), p<0.001] were independently associated with higher anti-S-RBD IgG values. A higher frequency of mild-moderate adverse effects was associated with the heterologous scheme, although it was well tolerated by all individuals and no medical assistance was required. Conclusion The heterologous SpV/Mod combination against SARS-CoV-2 is well tolerated and significantly increases humoral immune response as compared to the homologous SpV/SpV immunization.

Direct acting antiviral (DAA) therapy against hepatitis C virus (HCV) increases sustained virologic response rates. Nevertheless, drug resistance has occasionally been associated with failure to DAA. However, the information about the prevalence of NS5A and NS5B resistance‐associated substitutions (RASs) in Argentina is very scarce. In this study, we determine the prevalence of NS5A and NS5B resistances to treatment in Argentinean DAA treatment‐naïve patients chronically infected with genotype 1 (HCV‐1). In this retrospective cross‐sectional study, 108 HCV‐1‐infected patients were studied. RASs in NS5A and NS5B were analyzed by Sanger at baseline and phylogenetic analysis was performed. NS5A and NS5B RASs were detected in 25.8% and 6.3% of the analyzed sequences, respectively. The most frequent primary RASs for NS5A were L31M (7.5%) and Y93H (3.2%) and for NS5B was L159F (3.8%). No association between the presence of RASs and the outcome of DAA treatment was found in this study. Additionally, most of the Argentinean samples were randomly distributed among sequences around the world in the phylogenetic analysis. Only one significant Argentinean cluster was observed in both regions but without any particular RASs pattern. Baseline RASs in NS5A and NS5B were frequently observed in HCV‐1‐infected patients from Buenos Aires, Argentina but not related to treatment outcome. No clusters related to RASs transmission were observed in the phylogenetic analysis. The frequency of RASs detected in this study supports the need for more molecular epidemiology studies on RASs to adjust local treatment guidelines with the incorporation of autochthonous data.