It is not known whether non-ABO antibodies confer any protective effect against SARS-CoV-2 infection or COVID-19 severe illness alone or in conjunction with O blood group. This cohort study included 413 576 persons in Ontario, Canada with known ABO blood group and non-ABO antibody screen status, who subsequently underwent SARS-CoV-2 viral RNA polymerase chain reaction testing between January and November 2020. The risk of SARS-CoV-2 infection or COVID-19 severe illness was not associated with the presence of non-ABO antibodies, even among persons with O blood group. Latin America accounts for one-quarter of global COVID-19 cases and one-third of deaths. Inequalities in the region lead to barriers regarding the best use of diagnostic tests during the pandemic. There is a need for a simplified guideline, considering the region's health resources' low availability, international guidelines, medical literature, and local expertise. Nine experts from Latin American countries developed a simplified algorithm for COVID-19 diagnosis, using a modified Delphi method. Twenty-four questions related to diagnostic settings were proposed, followed by discussion of the literature and experts' experience. The algorithm considers three timeframes (≤7 days, 8-13 days, and ≥ 14 days) and discusses diagnostic options for each one. SARS-CoV-2 rRT-PCR is the test of choice from day 1 to day 14 after symptom onset or close contact, although antigen testing may be used in particular situations, from days 5 to 7. Antibody assays may be used for confirmation, mainly after day 14. If the clinical suspicion is very high, but other tests are negative, these assays may be used as an adjunct to decision-making from day 8 to day 13. The proposed algorithm aims to support COVID-19 diagnosis decision-making in Latin America. The proposed algorithm aims to support COVID-19 diagnosis decision-making in Latin America.The COVID-19 pandemic has fundamentally changed the way that public health professionals work and communicate. Over a very short time span, remote working arrangements have become the norm, and meetings have shifted online. Physical distancing measures have accelerated a trend toward digital communication and social exchange. At the same time, the work of epidemiologists has been held under a magnifying glass by journalists, governments and the general public, in a way not previously seen. With social media becoming an integral part of our society over the last decade, Twitter is now a key communication tool and platform for social networking among epidemiologists (#EpiTwitter). In this article, we reflect on the use of Twitter by field epidemiologists and public health microbiologists for rapid professional exchange, public communication of science and professional development during the pandemic and the associated risks. For those field epidemiologists new to social media, we discuss how Twitter can be used in a variety of ways, both at their home institutions and during field deployment. These include information dissemination, science communication and public health advocacy, professional development, networking and experience exchange. The efficacy of COVID-19 vaccines to generate immunological memory post-vaccination has not previously been studied. To assess immunological memory in previously SARS-CoV-2 infected individuals after a single dose of mRNA vaccine. Healthcare workers (n = 280) were enrolled after obtaining written informed consent and grouped under previously infected and no prior exposure (reverse transcription-polymerase chain reaction positive and negative, respectively). Blood was drawn at baseline and post-vaccination (single dose of COVISHIELD) for enumerating neutralizing antibodies by chemiluminescence and memory T- and B-cells by flow cytometry. Post vaccination, compared with the no prior exposure group, the previously infected group had higher levels of antibody response (1124.73 ± 869.13 vs 94.23 ± 140.06 AU/ml, p = 0.0001); CD4 memory T-cells central memory CCR7+CD45RA- (p = 0.0001), effector memory CCR7-/CD45RA- (p = 0.01); total CD8+ T-cells (p = 0.004); CD8+ naïve T-cells CCR7+CD45RA+ (p = 0.01); and memory B-cells CD20+CD27+ (p = 0.0001). Single-dose vaccination elicited higher neutralizing antibody response and protective immunity in individuals who had recovered from SARS-CoV-2 infection compared with those with no prior exposure. Single-dose vaccination elicited higher neutralizing antibody response and protective immunity in individuals who had recovered from SARS-CoV-2 infection compared with those with no prior exposure. Invasive Staphylococcus aureus (iSA) and group A Streptococcus (iGAS) impose significant health burdens globally. Both bacteria commonly cause skin and soft tissue infections (SSTIs), which can result in invasive disease. Understanding of the incidence of iSA and iGAS remains limited in settings with a high SSTI burden. Prospective surveillance for admissions with iSA or iGAS was conducted at the referral hospital in Fiji's Northern Division over 48 weeks between July 2018 and June 2019. There were 55 admissions for iSA and 15 admissions for iGAS (incidence 45.2 and 12.3 per 100,000 person-years, respectively). The highest incidence was found in patients aged ≥65 years (59.6 per 100,000 person-years for iSA and iGAS). The incidence of iSA was higher in indigenous Fijians (iTaukei) (71.1 per 100,000 person-years) compared with other ethnicities (incidence rate ratio 9.7, 95% confidence interval 3.5-36.9). SSTIs were found in the majority of cases of iSA (75%) and iGAS (53.3%). https://www.selleckchem.com/products/Dexamethasone.html Thirteen of the 14 iGAS strains isolated belonged to emm cluster D (n = 5) or E (n = 8). The case fatality rate was high for both iSA (10.9%) and iGAS (33.3%). The incidence of iSA and iGAS in Fiji is very high. SSTIs are common clinical foci for both iSA and iGAS. Both iSA and iGAS carry a substantial risk of death. Improved control strategies are needed to reduce the burden of iSA and iGAS in Fiji. The incidence of iSA and iGAS in Fiji is very high. SSTIs are common clinical foci for both iSA and iGAS. Both iSA and iGAS carry a substantial risk of death. Improved control strategies are needed to reduce the burden of iSA and iGAS in Fiji.