Booster dose of BNT162b2 in a CoronaVac primary vaccination protocol improves neutralization of SARS-CoV-2 Omicron variant

The emergence of the new SARS-CoV-2 Omicron variant, which is known to accumulate a huge number of mutations when compared to other variants, brought to light the concern about vaccine escape, especially from the neutralization by antibodies induced by vaccination. In this scenario, we evaluated the impact on antibody neutralization induction, against Omicron variant, by a booster dose of BNT162b2 mRNA vaccine after the CoronaVac primary vaccination scheme. The percentage of seroconverted individuals 30 and 60 days after CoronaVac scheme was 17% and 10%, respectively. After booster dose administration, the seroconvertion rate increased to 76.6%. The neutralization mean titer against Omicron in the CoronaVac protocol decreased over time, but after the booster dose, the mean titer increased 43.1 times, indicating a positive impact of this vaccine combination in the serological immune response.

SARS-CoV-2 infects, replicates, elevates angiotensin II and activates immune cells in human testes

Although much has been published since the first cases of COVID-19, there remain unanswered questions regarding SARS-CoV-2 impact on testes and the potential consequences for reproductive health. We investigated testicular alterations in deceased COVID-19-patients, the precise location of the virus, its replicative activity, and the molecules involved in the pathogenesis. We found that SARS-CoV-2 testicular tropism is higher than previously thought and that reliable viral detection in the testis requires sensitive nanosensoring or RT-qPCR using a specific methodology. Macrophages and spermatogonial cells are the main SARS-CoV-2 lodging sites and where new virions form inside the Endoplasmic Reticulum Golgi Intermediate Complex. Moreover, we showed infiltrative infected monocytes migrating into the testicular parenchyma. SARS-CoV-2 maintains its replicative and infective abilities long after the patients infection, suggesting that the testes may serve as a viral sanctuary. Further, infected testes show thickening of the tunica propria, germ cell apoptosis, Sertoli cell barrier loss, evident hemorrhage, angiogenesis, Leydig cell inhibition, inflammation, and fibrosis. Finally, our findings indicate that high angiotensin II levels and activation of mast cells and macrophages may be critical for testicular pathogenesis. Importantly, our data suggest that patients who become critically ill exhibit severe damages and may harbor the active virus in testes.

Effects of SARS-CoV-2 P.1 introduction and the impact of COVID-19 vaccination on the epidemiological landscape of Sao Jose Do Rio Preto, Brazil

The emergence of the new Brazilian variant of concern, P.1 lineage (Gamma), raised concern about its impact on the epidemiological profile of COVID-19 cases due to its higher transmissibility rate and immune evasion ability. Using 272 whole-genome sequences combined with epidemiological data, we showed that P.1 introduction in Sao Jose do Rio Preto, Sao Paulo, Brazil, was followed by the displacement of eight circulating SARS-CoV-2 variants and a rapid increase in prevalence two months after its first detection. Our findings support that the P.1 variant is associated with an increase in mortality risk and severity of COVID-19 cases in younger aged groups, which corresponds to the unvaccinated population at the time. Moreover, our data highlight the beneficial effects of vaccination indicated by a pronounced reduction of severe cases and deaths in immunized individuals, reinforcing the need for rapid and massive vaccination.

Comparison of histological and molecular diagnosis of Helicobacter pylori in benign lesions and gastric adenocarcinoma

A colonização do Helicobacter pylori está associada com gastrite crônica, úlcera péptica, metaplasia intestinal, adenocarcinoma e linfoma gástrico. O objetivo desse estudo foi comparar os resultados do diagnóstico histológico usado de rotina na detecção do H. pylori com o diagnóstico molecular. Foram utilizadas amostras de 80 lesões gástricas (gastrite crônica, gastrite atrófica, úlcera gástrica e metaplasia intestinal), 18 amostras de adenocarcinoma gástrico e 10 amostras de mucosa gástrica normal H. pylori negativas (controle). Todas as amostras foram avaliadas histologicamente (coloração com hematoxilina-eosina e Giemsa) e pela PCR com a amplificação dos genes antígeno espécie-específico (H3H4) e urease A (H5H6) do H. pylori e pelo gene humano CYP1A1, como controle da qualidade do DNA. Nas amostras de lesão benigna e adenocarcinoma gástrico, a infecção foi detectada em 43 per center (42/98) e 71 pe center (70/98), respectivamente, para os diagnósticos histológico e molecular (p = 0,0001). O teste de PCR detectou o H. pylori em 27,5 per center (22/80) das lesões gástricas benignas e em 50 per center (9/18) dos adenocarcinomas gástricos, com diagnóstico histológico negativo para essa bactéria. Cerca de 2,5 per center das amostras, exclusivamente de lesões benignas, com diagnóstico histológico positivo apresentaram resultado molecular negativo, para ambos os primers. Diferenças estatisticamente significantes foram encontradas entre os métodos histológico e molecular, em metaplasia intestinal (p = 0,0461) e adenocarcinoma gástrico (p = 0,0011), devido à subdetecção do H. pylori pelo método histológico, e provavelmente pela baixa densidade da bactéria conseqüente à atrofia severa da mucosa gástrica, nesses dois tipos de lesões. Nossos achados demonstram que o método de PCR é mais eficaz para diagnosticar a infecção por H. pylori, principalmente, em metaplasia intestinal e adenocarcinoma gástrico.