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BackgroundBy March 2022, around 34 million people in Colombia had received a complete scheme of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) including, mRNA-based vaccines, viral vectored coronavirus vaccines, or the inactivated whole virus vaccine. However, as several SARS-CoV-2 variants of concern (VOC) and interest (VOI) co-circulate in the country, determining the resistance level to vaccine-elicited neutralizing antibodies (nAbs) is useful to improve the efficacy of COVID-19 vaccination programs. MethodsMicroneutralization assays with the most prevalent SARS-CoV-2 lineages in Colombia during 2020-2021 were performed using serum samples from immunologically naive individuals between 9 and 13 weeks after receiving complete regimens of CoronaVac, BNT162b2, ChAdOx1, or Ad26.COV2.S. The mean neutralization titer (MN50) was calculated by the Reed-Muench method and used to determine differences in vaccine-elicited nAbs against the SARS-CoV-2 lineages B.1.111, P.1 (Gamma), B.1.621 (Mu), and AY.25.1 (Delta). ResultsThe most administered vaccines in the country, BNT162b2 and CoronaVac, elicited significantly different nAb responses against Mu, as the GMTs were 75.7 and 5.9-fold lower relative to the control lineage (B.1.111), while for Delta were 15.8 and 1.1-fold lower, respectively. In contrast, nAb responses against Mu and Delta were comparable between ChAd0x1-s and Ad26.COV2.S as the GMTs remained around 5 to 7-fold lower relative to B.1.111. ConclusionsThe emergence of SARS-CoV-2 variants in Colombia with a significant capacity to escape from vaccine-elicited nAbs indicates that a booster dose is highly recommended. Furthermore, other non-pharmacological measures should be retained in the vaccinated population.
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BackgroundGlobal surveillance programs for the virus that causes COVID-19 are showing the emergence of variants with mutations in the Spike protein, including the Mu variant, recently declared a Variant of Interest (VOI) by the World Health Organization. Genomic and laboratory surveillance is important in these types of variants because they may be more infectious or less susceptible to antiviral treatments and vaccine-induced antibodies. ObjectivesTo evaluate the sensitivity of the Mu variant (B.1.621) to neutralizing antibodies induced by the BNT162b2 vaccine. Study designThree of the most predominant SARS-CoV-2 variants in Colombia during the epidemiological peaks of 2021 were isolated. Microneutralization assays were performed by incubating 120 TCDI50 of each SARS-CoV-2 isolate with five 2-fold serial dilutions of sera from 14 BNT162b2 vaccinated volunteers. The MN50 titer was calculated by the Reed-Muench formula ResultsThe three isolated variants were Mu, a Variant of Interest (VOI), Gamma, a variant of concern (VOC), and B.1.111 that lacks genetic markers associated with greater virulence. At the end of August, the Mu and Gamma variants were widely distributed in Colombia. Mu was predominant (49%), followed by Gamma (25%). In contrast, B.1.111 became almost undetectable. The evaluation of neutralizing antibodies suggests that patients vaccinated with BNT162-2 generate neutralizing antibody titers against the Mu variant at significantly lower concentrations relative to B.1.111 and Gamma. ConclusionsThis study shows the importance of continuing with surveillance programs of emerging variants as well as the need to evaluate the neutralizing antibody response induced by other vaccines circulating in the country against Mu and other variants with high epidemiological impact. HighlightsO_LIMu and Gamma variants represented 49% and 25% of cases in Colombia by August 2021. C_LIO_LIIncreased proportion of SARS-COV-2 cases were mostly associated with Mu variant, despite being detected simultaneously with the VOC Gamma C_LIO_LIThe Mu variant remarkably escapes from neutralizing antibodies elicited by the BNT162b2-vaccine C_LIO_LILaboratory studies of neutralizing antibodies are useful to determine the efficacy of SARS-CoV-2 vaccines against VOC and VOI. C_LI
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Background: SARS-CoV-2 affects mainly occupational health populations. Healthcare workers are at constant risk of infection. The objective of this study was to determine the seroprevalence of SARS-CoV-2 in healthcare workers in Colombia. Methods: This study is a cross-sectional study focused on estimating the seroprevalence of SARS-CoV-2 antibodies in healthcare workers from 65 hospitals in 10 cities of Colombia during the second semester of 2020. The seroprevalence was determined using an automated immunoassay (Abbott SARS-CoV-2 CLIA IgG). The study included a survey to establish the sociodemographic variables and the risk of infection. Results: The global seroprevalence of antibodies against SARS-CoV-2 was 35% (95% Bayesian Confidence Interval 33%-37%). All the personnel reported the use of protective equipment. General services personnel and nurses presented the highest rates of seroprevalence among the healthcare workers. Low socioeconomic strata have shown a strong association with seropositivity. Conclusion: This study shows the occupational risk for SARS-CoV-2 infection among healthcare workers. Even though, all the personnel reported the use of protective equipment, the seroprevalence in the general services personnel and nurses was high. Also, it was observed a significant difference by city. The results could be used to perform prevention and control in this exposed population. However, further investigation of these is required to inform sources of infection to improve the control and occupational health practices.
