Reduction in COVID-19 Vaccine Effectiveness against SARS-CoV-2 Variants in Seoul according to Age, Sex, and Symptoms: A Test-Negative Case-Control Study.

BACKGROUND: We evaluated vaccine effectiveness (VE) against infections with SARS-CoV-2 variants of concern in Seoul, the capital of the Republic of Korea, having the highest population density in the country, under real-world conditions. METHODS: We evaluated the reduction in the effectiveness of mRNA and viral-vector COVID-19 vaccines against infection by the SARS-CoV-2 delta variant in a subpopulation from April 2021 to July 2021 who visited screening clinics in Seoul using a test-negative case-control study design. Moreover, we conducted a case-control study matching the ten-year-old age group, sex, healthcare workers, and five districts of Seoul, which are considered confounding factors. RESULTS: The full VE in the pre-delta-dominant period was 95.0% (95% confidence interval [CI]: 91.2-97.2); however, it decreased to 61.1% (95% CI: 53.2-67.6) during the delta-dominant period. Notably, we found that COVID-19 VE was significantly decreased in individuals aged ≥80 years (52.9%, 95% CI: -9.9-79.8), men (50.6 %, 95% CI: 39.4-59.8), and asymptomatic individuals (49.8%, 95% CI: 36.5-60.3) during the widespread SARS-CoV-2 delta variant circulation. CONCLUSIONS: Vaccine-mediated protection drastically declined during the delta-dominant period and in vulnerable groups. This study suggests the requirement for additional countermeasures, such as the administration of a booster vaccine, in vulnerable groups based on age, sex, and symptomatic manifestation.

The Biochemical Assessments of Cellular Oxidant - Antioxidant Status and Lipid Profile for Some of COVID-19 Vaccines (Pfizer, AstraZeneca and Sinopharm) in Vaccinated People of Wasit Province in Iraq

Background: Coronaviruses (SARS-CoV-2) cause COVID-19 pandemic in March, 2020, after Chinese scientists published the genome of the virus vaccine manufacturer produced several COVID-19 vaccines that aimed to induce a humoral and cellular immune response to prevent the fatality and harm caused by COVID-19. Existing study aimed to evaluate the biochemical efficiency of some of COVID-19 vaccines (Pfizer, AstraZeneca and Sinopharm) in vaccinated people of Wasit Province in Iraq by lipid profile estimation, Human SOD1 (Superoxide Dismutase 1, Soluble) and Human Malondialdehyde (MDA). Method(s): The current study sample included (55) individuals whom vaccinated with two shots of one of the three vaccines (Pfizer, AstraZeneca and Sinopharm) whom did not suffer from chronic health problems, and a control group of (35) unvaccinated individuals of both genders. Their age ranges from 18-45 years, they were divided into two age ranges (18-31 and 32-45 years) and their vaccination history was confirmed according to a special form. The blood samples were collected from fasting vaccinated individuals 2-4 weeks post the second dose of COVID-19 vaccine for the purpose of conducting lipid profile, SOD and MDA. RESULT(S): The data of serous endogenous oxidative-antioxidants balance showed a variation in the concentrations of malondialdehyde (MDA), its significant increase (P<=0.05) was observed in those vaccinated with the Pfizer vaccine for the first age range (31-18 years) and its insignificant decrease (P> 0.05) in the two Sinopharm and AstraZeneca vaccines in both age ranges and both genders comparing to the control group. Besides, the findings of estimating the serum level of enzyme Superoxide dismutase (SOD) was not significantly different (P> 0.05) between the vaccinated people of this study for all three vaccines and the control group for both age ranges and both genders. Additionally, the serum lipid profile levels (TG, LDL, HDL and VLDL) of the vaccinated individuals were not significantly changed (P>0.05) compared to the control group (unvaccinated individuals) except for the cleared variation in cholesterol level among the first age range for both genders compared to the control group. Conclusion(s): the findings of the present study showed that all the three targeted vaccines in the study (Pfizer, AstraZeneca and Sinopharm) have shown a high efficacy and safely on body oxidation balance and heart in terms of the biochemical assessment (MDA, SOD and lipid profile) of the healthy vaccinated participants. Copyright © 2022 Wolters Kluwer Medknow Publications. All rights reserved.

Evaluation of the Immunological Efficiency for Some of COVID-19 Vaccines (Pfizer, AstraZeneca and Sinopharm) among Vaccinated People of Wasit Province in Iraq

Background: Coronaviruses (SARS-CoV-2) cause Severe Acute Respiratory Syndrome COVID-19 pandemic in March, 2020. After Chinese scientists published the genome of the virus vaccine manufacturer produced several COVID-19 vaccines that aimed to induce a humoral and cellular immune response to prevent the fatality and harm caused by COVID-19. Existing study aimed to evaluate the immunological activity of some approved vaccines in terms of serological tests for antibodies (IgG and IgM) for the study groups in Wasit Governorate. Method(s): The current study sample included (55) individuals who were vaccinated with two doses of one of the three vaccines and did not suffer from chronic health problems, (35) unvaccinated individuals of both genders. Their age ranges from 18-45 years, they were divided into two age ranges (18-31 and 32-45 years) and their vaccination history was confirmed according to a special form. The blood samples were collected from vaccinated individuals 2-4 weeks after the second dose of COVID-19 vaccine for the purpose of conducting immunological assays for immunoglobulins (IgG, IgM) and C- reactive protein (CRP) using ELISA kits. Result(s): The results of serological immunoassay tests for (IgM) for the vaccinated participants, both age groups and both genders with the three Pfizer, AstraZeneca and Sinopharm vaccines were documented a positive percentage of (47 %), (64 %) and (42 %) and negative (53 %), (36%) and (58%) respectively. Whereas, the (IgG) among vaccinators with the same three vaccines was recorded a positive percentage (100%) and negative (0%) in terms of a significant rise (P<=0.05) in serum antibody levels (IgG) in all the three vaccines (Pfizer, AstraZeneca and Sinopharm) in both age ranges and for both genders compared to the control group (unvaccinated individuals). Conclusion(s): the findings of the present study, that all three vaccines (Pfizer, AstraZeneca and Sinopharm) have shown a high efficacy and safely against coronavirus disease (COVID-19) in terms of the immune responses of the vaccinators. Current study data indicated a non-significant difference among age ranges (18-31 and 32-45 year) and gender is not associated with IgG levels. Copyright © 2022 Wolters Kluwer Medknow Publications. All rights reserved.

A kinetic model considering the decline of antibody level and simulation about vaccination effect of COVID-19.

We build a model that consider the falling antibody levels and vaccination to assess the impact of falling antibody levels and vaccination on the spread of the COVID-19 outbreak, and simulate the influence of vaccination rates and failure rates on the number of daily new cases in England. We get that the lower the vaccine failure rate, the fewer new cases. Over time, vaccines with low failure rates are more effective in reducing the number of cases than vaccines with high failure rates and the higher the vaccine efficiency and vaccination rate, the lower the epidemic peak. The peak arrival time is related to a boundary value. When the failure rate is less than this boundary value, the peak time will advance with the decrease of failure rate; when the failure rate is greater than this boundary value, the peak time is delayed with the decrease of failure rate. On the basis of improving the effectiveness of vaccines, increasing the vaccination rate has practical significance for controlling the spread of the epidemic.

Omicron - The new SARS-CoV-2 challenge?

SARS-CoV-2 virus has infected nearly 300 M people worldwide and has been associated with over 6 M deaths by March 2022. Since the virus emergence in December 2019 in Wuhan, several new mutations have been described. The World Health Organization has developed a working name for these emerging variants according to their impact on the worldwide population. In this context a high alert has been paid to variants of concern (VOC) due to their high infectiousness and transmissibility patterns. The most recent VOC, Omicron (B.1.1.529), has become dominant in the shortest time ever and has placed Europe under an overwhelming and unprecedented number of new cases. This variant has numerous mutations in regions that are associated with higher transmissibility, stronger viral binding, affinity and antibody escape. Moreover, the mutations and deletions present in the spike protein suggest that the SARS-CoV-2 specific attachment inhibitors may not be the best option for Omicron therapy. Omicron is the dominant variant circulating worldwide and, at the end of February 2022, it was responsible for nearly all sequences reported to GISAID. Omicron is made up of several sublineages, where the most common are BA.1 and BA.2 (or Nextstrain clade 21K and 21L, respectively). At a global level, it is possible to say that the proportion of BA.2 has been increasing relative to BA.1 and in some countries it has been replacing it at high rates. In order to better assess the Omicron effectiveness on antibody escape, spread and infectious ability it is of the highest relevance to maintain a worldwide tight surveillance. Even though this variant has been associated with a lower death rate, it is important to highlight that the number of people becoming infected is concerning and that further unpredictable mutations may emerge as the number of infected people rises.

mRNA Vaccines as an Efficient Approach for the Rapid and Robust Induction of Host Immunity Against SARS-CoV-2.

Among the currently used COVID-19 vaccines, the mRNA-based vaccines drew the interest of the scientists because of its potent and versatile nature in mitigating the disease efficiently through increased translation as well as the robust modulation of the innate and adaptive immune responses within the host. The naked or lipid encapsulated mRNAs are usually optimized in order to formulate the vaccine. One of the interesting advantage of using mRNA vaccines is that such platform can even be used to mitigate other infectious diseases like influenza, zika, and rabies. However, the leading COVID-19 mRNA vaccines, i.e., mRNA-1273 and BNT162b2, have already been noticed to possess around 95% efficacy in provoking both the humoral and cell mediated immunity against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, causing the ongoing COVID-19 pandemic.