Background: Prior infection with SARS-CoV-2 has been reported to confer protection against reinfections. Because Peru has been affected by several variants of this virus, it is an ideal location to better explore this phenomenon. In this study, we aim to evaluate protection of prior SARS-CoV-2 infection against reinfection by variants during the COVID-19 pandemic in Peru. Methods: A nested case-control study was carried out, using national data from Peru between 2021 and 2023. Five study periods were defined, delimited by the predominance of the main SARS-CoV-2 variants circulating during the pandemic. Cases were paired with controls in a 1 to 4 rate by sex, age, region, being a health worker, and the week of infection. Protection was calculated using conditional logistic regression to estimate odds ratios (OR) with 95% confidence intervals (95% CI) expressed as (1-OR) x100. Results: Protection from prior infection against SARS-CoV-2 reinfection was 86.3% (95% CI, 81.8 to 89.7) for Lambda, 73.0% (95% CI, 62.9 to 80.3) for Gamma, 84.7% (95% CI, 82.1 to 86.9) for Delta, 34.9% (95% CI, 25.5 to 43.1) for Omicron BA.1, 67.0% (95% CI, 58.7 to 73.6) for Omicron BA.2.12.1, 49.1% (95% CI, 40.5 to 56.5) for Omicron BA.4, 44.8% (95% CI, 39.9 to 49.3) for Omicron BA.5, 29.4% (95% CI, 18.2 to 39.1) for Omicron BQ, and 8.6% (95% CI, -0.5 to 16.9) for Omicron XBB. Conclusions: Prior infection provides a significant protection against SARS-CoV-2 reinfection episodes, although this varies widely among the different Omicron sublineages.

To systematize published laboratory methods to inactivate Mycobacterium tuberculosis (MTB) and to describe their effectiveness. We carried out a review of the scientific literature to identify the publications that reported methods for the inactivation of MTB, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. The search addressed inactivation methodologies used in Public health laboratories for the treatment of biological material and only included studies reporting the efficacy of the method. The database used were PubMed (National Library of Medicine) and LILACS (Latin American and Caribbean Literature in Health Sciences). We evaluated the quality of the studies with the JBI (Joanna Briggs Institute) Critical Instrument Appraisal Checklist. We included 14 publications meeting the established inclusion and exclusion criteria. These 14 studies actually described a total of 35 inactivation methods. Most of them combined heat treatment with some chemical or enzymatic agent, and there were very few applying a single strategy. Twenty-four (68.57%) methods demonstrated significant efficacy in inactivating MTB. The systematic review identified 35 methods of inactivation of MTB, published in 14 studies. Most of the methods combined physical treatment techniques, especially heat, with chemical and/or enzymatic treatment techniques, obtaining mostly good results in preventing the reproduction of the microorganism. PROSPERO (International Prospective Register of Ongoing Systematic Reviews) (Code CRD42024503621).

BACKGROUND:During 2021, Peru started the vaccination against SARS-CoV-2 using the BBIBP-CorV inactivated virus vaccine for health care workers (HCW). We aim to evaluate the effectiveness of the BBIBP-CorV vaccine to prevent SARS-CoV-2 infection and deaths among HCWs.METHODS:Retrospective cohort study, from February 9 to June 30, 2021, using national registries of health care workers, laboratory tests for SARS-CoV-2 and deaths. We calculated the vaccine effectiveness for preventing laboratory-confirmed SARS-CoV-2 infection, COVID-19-mortality, and all-cause mortality among partially immunized and fully immunized HCWs. An extension of Cox proportional hazards regression was used to model the mortality results, and Poisson regression was used to model SARS-CoV-2 infection.RESULTS:The study included 606,772 eligible HCWs, the mean age was 40 (IQR: 33.0, 51.0). In fully immunized HCW, the effectiveness for preventing all-cause mortality was 83.6 (95% CI: 80.2 to 86.4), 88.7 (95% CI: 85.1 to 91.4) for preventing COVID-19 mortality, and 40.3 (95% CI 38.9 to 41.6) for preventing SARS-CoV-2 infection.CONCLUSION:The BBIBP-CorV vaccine showed high levels of effectiveness for preventing all-cause and COVID-19 deaths among fully immunized HCW. These results were consistent within different subgroups and sensitivity analyses. However, the effectiveness for preventing infection was suboptimal in this particular setting.

The massive sequencing of severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) and global genomic surveillance strategies allowed the detection of many variants of concern and interest. The variant of interest Lambda (C.37), which originated in South America, has been the most prevalent in Peru and Chile, but its dispersion in other continents still remains unknown. The current study aims to determine the phylogenetic relationship among C.37 isolates worldwide, focusing on spike mutations to understand the spread of Lambda in pandemics. A total of 7441 sequences identified as C.37 were downloaded from the GISAID database; local analysis was carried out to identify spike mutations and phylogenetic analysis was carried out to determine the rate of spread of the virus. Our results showed some spike mutations of Lambda that allowed us to detect small local outbreaks in different countries that occurred in the past and identify several clades that have not yet been designated. Although the lineage C.37 is not epidemiologically relevant in Europe or North America, the endemic behavior of this variant in Peru had a major impact on the second SARS-CoV-2 wave.

Background Coronavirus disease 2019 (COVID-19) infection is a major public health problem in the world and reinfections are becoming more frequent. Our main objective was to describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the capital of Lima and Callao, Peru. Methods We searched in the Peruvian laboratory information system from April 2020 up to May 2021, looking for cases having 2 positive molecular tests for SARS-CoV-2 with more than 90 days between them. We performed genomic sequencing to the available pairs of samples and described the clinical characteristics, epidemiological impact, and genomic analysis of the confirmed reinfections. Results There were 1 694 164 people with a positive diagnostic test for SARS-CoV-2 in Lima/Callao during the study period. Of these, 1695 had 2 positive molecular tests with more than 90 days between them. Two hundred eleven had both samples available for genomic analysis according to our selection criteria, and these were retrieved and submitted to sequencing. Thirty cases were confirmed to be SARS-CoV-2 reinfections with 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection and accounted for 19 (63.3%) of the 30 cases. Conclusions We report 30 cases of confirmed SARS-CoV-2 reinfections. The Lambda variant was the most common cause of the second infections, in concordance with its predominant circulation during Peru’s second wave. This report describes the largest series of confirmed reinfections by SARS-CoV-2 in Latin America. We describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 in Lima and Callao, durante la segunda ola en Peru. The Lambda variant (C.37) was the most common cause of the second infections.

BACKGROUND:Studies have reported evidence about the effectiveness of a third dose with BNT162b2 for preventing hospitalization and death by COVID-19. However, there is little evidence regarding other primary vaccine schedules such as BBIBP-CorV and ChAdOx1-S. We estimated the relative vaccine effectiveness (RVE) of the booster dose versus the primary regimens of COVID-19 vaccines based on BBIBP-CorV, ChAdOx1-S, or BNT162b2 for preventing death during the Omicron wave in Peruvian adult people.METHODS:We carried out a nested case-control study with a risk set sampling of controls using data from Peru between December 20, 2021, and February 20, 2022 (during the Omicron wave). Data on vaccination, COVID-19 tests and deaths were collected from national surveillance databases. We performed conditional logistic regression models to estimate the RVE on the adult population. In addition, we executed sub-group analysis per age group (18 to 59 years, and 60 years or more) and per primary regime (based on BNT162b2, BBIBP-CorV, or ChAdOx1-S).RESULTS:Of the 11,188,332 people eligible to enter the study 1,974 met the case definition (death from COVID-19) and were matched to 9,183 controls. The overall RVE of a third dose to prevent death was 87.2% (84.2%-89.7%), which varied according to the primary regime (87.3% for BNT162b2, 82.0% for BBIPB-CorV-2, and 79.5% for ChAdOx-S). In older adults, the RVE was 87.1%, without significant variations according to the primary regime (86.1% for BNT162b2, 86.1 for BBIBP-CorV, and 82% for ChAdOx-S).CONCLUSIONS:The booster) dose of vaccine against COVID-19 had a high RVE for preventing death by COVID-19 in the Peruvian population in all primary regimes of vaccines during the Omicron wave. This effect was consistent in people over 60 years of age, the group most vulnerable to die from this infection.

Objetivos. Evaluar la respuesta de preparados IgG por ELISA utilizando rígidos Wuhan y Lambda en trabajadores de la salud con y sin antecedentes de infección por SARS-CoV-2 antes de la inmunización con la primera y segunda dosis de la vacuna Sinopharm (BBIBP-CorV). Materiales y métodos.Se realizó un estudio analítico en trabajadores sanitarios mayores de 18 años. Se incluyeron 51 participantes con antecedentes y 100 participantes sin antecedentes de infección por SARS-CoV-2, que recibieron dos dosis de la vacuna Sinopharm. Los obtenidos IgG se evaluaron 21 días después de la primera dosis, 21 días después de la segunda dosis y 3 meses después de la segunda dosis mediante ELISA interno utilizando el endurecimiento completo de la variante de Wuhan (B.1.1) y la variante lambda ( C-37) del virus SARS-CoV-2. Resultados.Ambos grupos mostraron un gran aumento en el porcentaje de personas con resultados después de la segunda dosis, sin embargo, este porcentaje llegó a los 3 meses después de la segunda dosis. La diferencia entre el índice de estudios medidos por ELISA con variante de Wuhan versus ELISA con variante lambda fue significativa (p<0.001). Conclusiones. Hay un aumento significativo en la presencia de estudios tipo IgG después de 15 días de la segunda dosis de vacunación BBIBP-CorV en participantes sin infección previa y una disminución después de 3 meses de la segunda dosis en la proporción de índices de reactividad de estudios IgG en ELISA con la variante de diagnóstico como con ELISA con la variante lambda.

BACKGROUND:The administration of a third (booster) dose of COVID-19 vaccines in Peru initially employed the BNT162b2 (Pfizer) mRNA vaccine. The national vaccination program started with healthcare workers (HCW) who received BBIBP-CorV (Sinopharm) vaccine as primary regimen and elderly people previously immunized with BNT162b2. This study evaluated the reactogenicity and immunogenicity of the "booster" dose in these two groups in Lima, Peru.METHODS:We conducted a prospective cohort study, recruiting participants from November to December of 2021 in Lima, Peru. We evaluated immunogenicity and reactogenicity in HCW and elderly patients previously vaccinated with either two doses of BBIBP-CorV (heterologous regimen) or BTN162b2 (homologous regimen). Immunogenicity was measured by anti-SARS-CoV-2 IgG antibody levels immediately before boosting dose and 14 days later. IgG geometric means (GM) and medians were obtained, and modeled using ANCOVA and quantile regressions.RESULTS:The GM of IgG levels increased significantly after boosting: from 28.5±5.0 AU/mL up to 486.6±1.2 AU/mL (p<0.001) which corresponds to a 17-fold increase. The heterologous vaccine regimen produced higher GM of post-booster anti-SARS-CoV-2 IgG levels, eliciting a 13% increase in the geometric mean ratio (95%CI: 1.02-1.27) and a median difference of 92.3 AU/ml (95%CI: 24.9-159.7). Both vaccine regimens were safe and well tolerated. Previous COVID-19 infection was also associated with higher pre and post-booster IgG GM levels.CONCLUSION:Although both boosting regimens were highly immunogenic, two doses of BBIBP-CorV boosted with BTN162b2 produced a stronger IgG antibody response than the homologous BNT162b2 regimen in the Peruvian population. Additionally, both regimens were mildly reactogenic and well-tolerated.

OBJECTIVES . To evaluate the IgG antibody response by ELISA using Wuhan and Lambda antigens in health care workers with and without history of SARS-CoV-2 infection prior to immunization with the first and second doses of Sinopharm vaccine (BBIBP-CorV). MATERIALS AND METHODS . An analytical study was carried out in health care workers over 18 years of age. Fifty-one participants with history and 100 participants without history of SARS-CoV-2 infection, who received two doses of Sinopharm vaccine, were included. IgG antibodies were assessed 21 days after the first dose, 21 days after the second dose and 3 months after the second dose by in-house ELISA using the complete antigen of the Wuhan variant (B.1.1) and lambda variant (C-37) of SARS-CoV-2 virus. RESULTS . Both groups showed a large increase in the percentage of people with antibodies after the second dose, however, this percentage decreased 3 months after the second dose. The difference between the antibody index measured by ELISA with Wuhan variant antigen versus the ELISA with lambda variant was significant (p<0.001). CONCLUSIONS . There is a significant increase in the presence of IgG type antibodies after 15 days of the second dose of BBIBP-CorV vaccination in participants without previous infection and a decrease after 3 months of the second dose in the ratio of IgG antibody reactivity indexes in ELISAs with the variant antigen as with ELISAs with the lambda variant.

Se presenta el caso de 9 pacientes reportados en el contexto de la alerta sanitaria por el aumento de casos de infección por el virus de Monkeypox en el mundo en países no endémicos. Es importante conocer de forma práctica los criterios epidemiológicos y clínicos más importantes para el descarte de viruela símica en el actual contexto de trasmisión en el Perú. Se discute los criterios de los casos confirmados respecto a otras enfermedades que son parte del diagnóstico diferencial como varicela, síndrome mano pie boca, entre otros.

OBJECTIVE:To describe the results of laboratory tests performed on biological samples from patients with Guillain-Barré syndrome (GBS) submitted to the Instituto Nacional de Salud (INS) between 2018 and 2019.MATERIALS AND METHODS:We conducted an observational study on patients with GBS, by using data from the epidemiological surveillance system. Biological samples, previously analyzed at the INS, were obtained to study arboviruses, respiratory viruses, enteroviruses and enterobacteria, among others.RESULTS:A total of 2,051 specimens were obtained from 906 patients with GBS. Three patients tested positive for dengue and three for Zika. In 19 patients, the stool culture was positive for Campylobacter jejuni. Phylogenetic analysis of 10 Campylobacter jejuni strains classified them as genotype ST2993, which was previously reported in China and associated to a GBS outbreak. Twelve cerebrospinal fluid samples tested positive for enterovirus by PCR in 2018, but none could be verified by culture or complete genome sequencing during the study. One patient was positive for influenza A, two for influenza B, two for adenovirus, five for respiratory syncytial virus, and ten for rinovirus.CONCLUSION:Several pathogens were found in samples from patients with GBS. However, we found that the genotype ST2993 of Campylobacter jejuni was the most likely causal agent, a pathogen that is related to GBS outbreaks in different continents. It is necessary to confirm this hypothesis with additional analytical studies and it is important to describe the transmission mechanism of C. jejuni genotype ST2993 in order to implement prevention and control measures.

Background We determined the frequency of genetic polymorphisms in three anti-TB drug metabolic proteins previously reported: N-acetyltransferase 2 (NAT2), cytochrome P450 2E1 (CYP2E1) and arylacetamide deacetylase (AADAC) within a Peruvian population in a cohort of TB patients. We included 395 participants completed their anti-tuberculosis treatment. Results ∼74% of the participants are carriers of slow metabolizer genotypes: NAT2*5, NAT2*6 and NAT2*7, which increase the sensitivity of INH at low doses and increase the risk of drug-induced liver injuries. ∼ 64% are homozygous for the wild-type CYP2E1*1A allele, which could increase the risk of hepatotoxicity. However, 16% had a NAT2 fast metabolizer phenotype which could increase the risk of acquiring resistance to INH, thereby increasing the risk of multidrug-resistant (MDR) or treatment failure. The frequency of rs1803155 (AADAC*2 allele) was higher (99.9%) in Peruvians than in in European American, African American, Japanese, and Korean populations. Conclusions This high prevalence of slow metabolizers for Isoniazid in the Peruvian population should be further studied and considered to help individualize drug regimens, especially in countries with a great genetic diversity like Peru. These data will help the Peruvian National Tuberculosis Control Program develop new strategies for therapies.

Peru has the highest burden of multidrug-resistant tuberculosis in the Americas region. Since 1999, the annual number of extensively drug-resistant tuberculosis (XDR-TB) Peruvian cases has been increasing, becoming a public health challenge. The objective of this study was to perform genomic characterization of Mycobacterium tuberculosis strains obtained from Peruvian patients with XDR-TB diagnosed from 2011 to 2015 in Peru. Whole genome sequencing (WGS) was performed on 68 XDR-TB strains from different regions of Peru. 58 (85.3%) strains came from the most populated districts of Lima and Callao. Concerning the lineages, 62 (91.2%) strains belonged to the Euro-American Lineage, while the remaining 6 (8.8%) strains belonged to the East-Asian Lineage. Most strains (90%) had high-confidence resistance mutations according to pre-established WHO-confident grading system. Discordant results between microbiological and molecular methodologies were caused by mutations outside the hotspot regions analysed by commercial molecular assays ( rpoB I491F and inhA S94A). Cluster analysis using a cut-off ≤ 10 SNPs revealed that only 23 (34%) strains evidenced recent transmission links. This study highlights the relevance and utility of WGS as a high-resolution approach to predict drug resistance, analyse transmission of strains between groups, and determine evolutionary patterns of circulating XDR-TB strains in the country.