What Happens to the Immune System after Vaccination or Recovery from COVID-19?

Due to its leading role in fighting infections, the human immune system has been the focus of many studies in the context of Coronavirus disease 2019 (COVID-19). In a worldwide effort, the scientific community has transitioned from reporting about the effects of the novel coronavirus on the human body in the early days of the pandemic to exploring the body's many immunopathological and immunoprotecting properties that have improved disease treatment and enabled the development of vaccines. The aim of this review is to explain what happens to the immune system after recovery from COVID-19 and/or vaccination against SARS-CoV-2, the virus that causes the disease. We detail the way in which the immune system responds to a SARS-CoV-2 infection, including innate and adaptive measures. Then, we describe the role of vaccination, the main types of COVID-19 vaccines and how they protect us. Further, we explain the reason why immunity after COVID-19 infection plus a vaccination appears to induce a stronger response compared with virus exposure alone. Additionally, this review reports some correlates of protection from SARS-CoV-2 infection. In conclusion, we reinforce that vaccination is safe and important in achieving herd immunity.

Genotyping of Giardia duodenalis in vegetables cultivated with organic and chemical fertilizer from street markets and community vegetable gardens in a region of Southern Brazil.

Background: In order to investigate the occurrence of Giardia duodenalis and its genotypes in vegetables that are consumed raw, we analyzed samples cultivated with organic or chemical fertilizer, sold in street markets and from community vegetable gardens in an urban area located in Southern Brazil. Methods: We analyzed 130 samples of vegetables such as crisp lettuce, regular lettuce, kale, chicory and rocket, from street markets, and 130 from community gardens. From each sample, 50 g were washed in Tween 80 solution (1%) and the solution obtained was filtered through a cellulose acetate membrane. The retained material was used for DNA extraction with the commercial kit Purelink®. GDH gene was amplified by semi-nested PCR using the GDHeF, GDHiR and GDHiF primers. Positive samples were genotyped using the PCR-RFLP technique with the restriction enzyme NlaIV. Results: We obtained 7.3% (19/260) positive samples for G. duodenalis, both from street markets (10/130) and from community gardens (9/130), including organic and non-organic products. The assemblage AI was predominant, but assemblages B and E were also found. Conclusions: The molecular technique revealed genotypes with zoonotic potential, evidencing the importance of investigating commercialized vegetables that are consumed raw and establishing a more rigid quality control.

First Detection of Toxoplasma gondii DNA in the Fresh Leafs of Vegetables in South America.

Despite the high dispersion of Toxoplasma gondii oocysts in the environment, there are few studies investigating their presence in vegetables consumed by the general population. This has led us to investigate its occurrence in raw vegetables. A total of 238 samples of vegetables were collected, including crisp lettuce, regular lettuce, chicory, rocket, and parsley, both organic and nonorganic, locally in northwestern Parana, Southern Brazil. Each sample (50 g) was washed and filtered separately. A PCR was performed to detect the parasite DNA from the sediment of each sample, using B1 (B22-23) and Toxo4-5 primers. We found contamination in 3.8% of the samples, 0.8% with the primer Toxo4-5 and 2.9% with B22-B23. The results were positive in 0.6% (1/62) of the samples of smooth lettuce, 3.7% (4/106) of crisp head lettuce, 5.0% (2/40) of chicory, 14.3% (1/7) of rocket, and 20% (1/5) of parsley. These data show the contamination by T. gondii in raw vegetables directly from production sites and stores, in both organic and nonorganic samples.