Low prevalence of influenza viruses and predominance of A(H3N2) virus with respect to SARS-CoV-2 during the 2021-2022 season in Bulgaria.

Social distancing, mask-wearing, and travel restrictions during the COVID-19 pandemic have significantly impacted the spread of influenza viruses. The objectives of this study were to analyze the pattern of influenza virus circulation with respect to that of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Bulgaria during the 2021-2022 season and to perform a phylogenetic/molecular analysis of the hemagglutinin (HA) and neuraminidase (NA) sequences of representative influenza strains. Influenza infection was confirmed using real-time reverse transcription polymerase chain reaction in 93 (4.2%) of the 2193 patients with acute respiratory illness tested wherein all detected viruses were subtyped as A(H3N2). SARS-CoV-2 was identified in 377 (24.3%) of the 1552 patients tested. Significant differences in the incidence of influenza viruses and SARS-CoV-2 were found between individual age groups, outpatients/inpatients, and in the seasonal distribution of cases. Two cases of coinfections were identified. In hospitalized patients, the Ct values of influenza viruses at admission were lower in adults aged ≥65 years (indicating higher viral load) than in children aged 0-14 years (p < 0.05). In SARS-CoV-2-positive inpatients, this association was not statistically significant. HA genes of all A(H3N2) viruses analyzed belonged to subclade 3C.2a1b.2a. The sequenced viruses carried 11 substitutions in HA and 5 in NA, in comparison to the vaccine virus A/Cambodia/e0826360/2020, including several substitutions in the HA antigenic sites B and C. This study revealed extensive changes in the typical epidemiology of influenza infection, including a dramatic reduction in the number of cases, diminished genetic diversity of circulating viruses, changes in age, and seasonal distribution of cases.

Transplacental transmission of SARS-CoV-2 immunoglobulin G antibody to infants from maternal COVID-19 vaccine immunization before pregnancy.

The coronavirus disease 2019 (COVID-19) vaccine generates functional antibodies in maternal circulation that are detectable in infants, while the information is restricted to the usage of COVID-19 vaccine during pregnancy. In this study, we aimed to evaluate the effect of maternal COVID-19 vaccines before pregnancy. Infants were included from mothers with no inactivated COVID-19 vaccine, 1-, 2-, and 3-dose before pregnancy, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) antibodies were tested. Comparative analysis was done between the groups. A total of 130 infants were enrolled in the study. Significantly higher levels of SARS-CoV-2 IgG antibodies in infants born to mothers with 3-dose COVID-19 vaccine before pregnancy compared with 1- and 2-dose groups (p < 0.0001). The levels of antibodies decreased significantly with age in infants born to mothers with the 3-dose COVID-19 vaccine before pregnancy (r = -0.338, p = 0.035), and it was still higher than that 2-dose COVID-19 vaccine group. The maternal SARS-CoV-2 antibodies produced from the inactivated COVID-19 vaccine before pregnancy can be transferred to newborns via the placenta. Maternal immunization with 3-dose of the COVID-19 vaccine before pregnancy could be more beneficial for both mothers and infants.

The immunodominance of RBD antigen of delta variant as vaccine candidate against SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel subset of coronavirus that causes coronavirus disease 2019 (COVID-19), but vaccine development is hampered by the high mutation of virus This article is protected by copyright. All rights reserved.

Omicron variant of SARS-CoV-2: Genomics, transmissibility, and responses to current COVID-19 vaccines.

Currently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide as an Omicron variant. This variant is a heavily mutated virus and designated as a variant of concern by the World Health Organization (WHO). WHO cautioned that the Omicron variant of SARS-CoV-2 held a very high risk of infection, reigniting anxieties about the economy's recovery from the 2-year pandemic. The extensively mutated Omicron variant is likely to spread internationally, posing a high risk of infection surges with serious repercussions in some areas. According to preliminary data, the Omicron variant of SARS-CoV-2 has a higher risk of reinfection. On the other hand, whether the current COVID-19 vaccines could effectively resist the new strain is still under investigation. However, there is very limited information on the current situation of the Omicron variant, such as genomics, transmissibility, efficacy of vaccines, treatment, and management. This review focused on the genomics, transmission, and effectiveness of vaccines against the Omicron variant, which will be helpful for further investigation of a new variant of SARS-CoV-2.

Adverse events following immunization of COVID-19 (Covaxin) vaccine at a tertiary care center of India.

The study aimed to assess the adverse events following COVID-19 vaccine (Covaxin) immunization at a tertiary care institution and also assess the predictors of the adverse events following immunization (AEFI). The prospective observational study was conducted in a tertiary care institute among the Covaxin beneficiaries between June 28 and September 6, 2021. A total of 1826 participants were assessed for any local or systemic adverse events after seven days of vaccination. A telephonic interview was conducted, and the beneficiaries were assessed according to the adverse event grading. A total of 1826 participants were assessed for AEFI, and 544 (29.8%) reported at least one of the AEFI. No severe adverse events were reported, and about 1.6% had moderate AEFI. Pain at the injection site (14.6%), fever (9.7%), and myalgia (5.9%) were the common adverse events reported by the participants. AEFI incidence was higher in the first dose (38.1%) when compared to the second dose (26.4%), and this finding was significant with a p < 0.001. The major factors associated with AEFI were female sex, history of an allergic reaction, presence of comorbidities, acute infection in the past 3 months, and intake of chronic medications. Precaution needs to be taken while vaccinating individuals having allergies, comorbidities, acute infection in the last 3 months, and individuals on chronic medication.

The effectiveness of mRNA-1273 vaccine against COVID-19 caused by Delta variant: A systematic review and meta-analysis.

We aimed to perform meta-analyses to summarize the overall effectiveness of the mRNA-1273 vaccine against COVID-19 caused by the Delta variant from real-world studies. A systematic literature search with no language restriction was performed in electronic databases to identify eligible observational studies that reported the effectiveness of the mRNA-1273 vaccine to prevent reverse transcription-polymerase chain reaction (RT-PCR) confirmed COVID-19 caused by Delta variant of SARS-CoV-2 (B.1.617.2). A random-effects meta-analysis model was used to estimate the pooled odds ratio (OR) at a 95% confidence interval (CI), and the vaccine effectiveness was indicated as (pooled OR - 1)/OR. Five studies were included for this systematic review and meta-analysis. The meta-analysis revealed that the administration of mRNA-1273 vaccine protected against RT-PCR confirmed COVID-19 caused by Delta variant ≥21 days post first dose, with pooled vaccine effectiveness of 66% (95% CI: 65%-67%), as well as ≥14 days after the second dose, with pooled vaccine effectiveness of 91% (95% CI: 84%-95%). In conclusion, the mRNA-1273 vaccine offers a substantial protection rate against RT-PCR confirmed COVID-19 caused by the Delta variant upon full vaccination, although with slightly reduced effectiveness relative to other strains of SARS-CoV-2.

Surveillance genome sequencing reveals multiple SARS-CoV-2 variants circulating in central Texas, USA, with a predominance of delta variant and review of vaccine breakthrough cases.

As surges in the COVID-19 pandemic have continued worldwide, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has mutated, spawning several new variants, and impacting, to various degrees, transmission, disease severity, diagnostics, therapeutics, and natural and vaccine-induced immunity. Baylor Scott & White Health has implemented, along with laboratory diagnosis, SARS-CoV-2 sequencing to identify variants in its geographical service area. We analyzed virus sequencing results of specimens collected across Central Texas and found dramatic changes in variant distribution in the first half of 2021. The alpha variant (B 1.1.7) became predominant at week 13 and continued dominance until week 25. A growth rate of 1.20 (R2 = 0.92) for the first 15 weeks was noted and this growth gradually declined to -0.55 (R2 = 0.99) for the final 13 weeks. Currently, B.1.1.7 is being displaced with B.1.617.2 at a 0.58 growth rate (R2 = 0.97). We also investigated vaccine breakthrough cases (VBCs) within our healthcare system and present clinical data on 28 symptomatic patients.

Biphasic anaphylaxis after exposure to the first dose of Pfizer-BioNTech COVID-19 mRNA vaccine.

In the setting of a coronavirus disease 2019 (COVID-19) global pandemic and increased disease burden, vaccination has become one of the major solutions. With the increase in vaccination numbers worldwide, it is important to stay vigilant to the potential side effects and life-threatening complications of such vaccines. We report the case of a 30-year-old male with a biphasic allergic reaction post messenger (mRNA) Pfizer-BioNTech COVID-19 vaccination. Several reports of allergic reactions have been cited in the literature after the administration of the mRNA Pfizer-BioNTech COVID-19 vaccine. It is important to keep a high index of suspicion in severe anaphylactic cases as some patients may have a recurrence of symptoms after discharge. It is crucial to acknowledge the potential risk of anaphylaxis in select individuals and have the appropriate measures in place to deal with adverse events. In case of severe symptoms, the administration of epinephrine is advised to prevent the development of a delayed biphasic anaphylactic reaction.

Lack of immune response after mRNA vaccination to SARS-CoV-2 in a solid organ transplant patient.

The recent approval and distribution of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been a major development in the fight against the current coronavirus disease 2019 (COVID-19) pandemic. The first two vaccines approved in the United States, mRNA-1273, and BNT162b2, are both messenger RNA (mRNA) based and highly effective in immunocompetent persons, but efficacy in patients on immunosuppressants has not been established. Additionally, data suggests these patients are less likely than immunocompetent people to develop neutralizing antibodies after COVID-19 infection. Given the high risk of poor outcomes in organ transplant and immunosuppressed patients, effective vaccination is paramount in this group. We present the first reported case of a solid organ transplant patient who failed to achieve seroconversion after two doses of mRNA vaccine. This case has significant implications about how immunosuppressed patients should be counseled about SARS-CoV-2 vaccination and the protection provided. Physicians should remain clinically suspicious for infection with SARS-CoV-2 despite vaccination status in solid organ transplant patients.

Endemic infections, vaccinations, and variability of SARS-COV2 worldwide epidemiology: A cross-sectional study.

The present article aims to analyze epidemiologic aspects of the novel coronavirus pandemic (COVID-19) over different countries across the globe. While analyzing the overall spread of the disease, clusters of countries could be identified where the population-adjusted number of cases and mortality rates (MRs) were significantly different from the others. To draw a comparison over the countries at the same stage of infection, the nature and spread of the infection was evaluated at the 90th day of the pandemic for each country. It was observed that the countries with prevalent malarial transmission tended to have lesser population-adjusted COVID-19 caseloads. It was further observed that high population coverage of the Bacillus Calmette-Guérin vaccination was negatively associated with population-adjusted caseloads and MRs due to COVID-19. The present cross-sectional study is an attempt to bring in several social, economic, and structural confounders into understanding of the nature and spread of this novel pandemic globally.