Abstract:The aims of this study were: to determine the incidence of Severe Acute Respiratory Syndrome Coronavirus‐2 (SARS‐CoV‐2) infection among vaccinated healthcare workers (HCWs), assess risk factors associated with the vaccine breakthrough (BT), and compare the effectiveness of vaccine manufacturers against SARS‐CoV‐2 variant of concern among HCWs in Duhok governorate. It is a multicenter retrospective cohort study, which enrolled 944 HCWs through March 2022. COVID‐19 vaccinated HCWs aging 18 and above were include… Show more
“…showed that the 2 viral-vector vaccines JNJ-78436735 (Ad26.COV2.S) and AstraZeneca vaccine (ChAdOx1 nCoV-19) were associated with a higher risk of breakthrough infection compared to BNT162b2 [ 35 ]. This is concordant with a study conducted in Iraq, showing that the AstraZeneca vaccine was more associated with breakthrough infections in comparison with mixed vaccines or BNT162b2 vaccines [ 36 ]. A study in the United Kingdom including a group of vaccinated index patients and unvaccinated ones, compared the probability of infection of people in contact with these 2 groups.…”
Since March 2020, the COVID-19 pandemic has swiftly propagated, triggering a competitive race among medical firms to forge vaccines that thwart the infection. Lebanon initiated its vaccination campaign on February 14, 2021. Despite numerous studies conducted to elucidate the characteristics of immune responses elicited by vaccination, the topic remains unclear. Here, we aimed to track the progression of anti-spike SARS-CoV-2 antibody titers at two-time points (T1: shortly after the second vaccination dose, T2: six months later) within a cohort of 201 adults who received Pfizer-BioNTech (BNT162b2), AstraZeneca, or Sputnik V vaccines in North Lebanon. Blood specimens were obtained from participants, and antibody titers against SARS-CoV-2 were quantified through the Elecsys-Anti-SARS-CoV-2 S assay (Roche Diagnostics, Switzerland). We used univariate analysis and multivariable logistic regression models to predict determinants influencing the decline in immune response and the occurrence of breakthrough infections among vaccinated patients. Among the 201 participants, 141 exhibited unchanging levels of antibody titers between the two sample collections, 55 displayed waning antibody titers, and only five participants demonstrated heightened antibody levels. Notably, age emerged as the sole variable significantly linked to the waning immune response. Moreover, the BNT162b2 vaccine exhibited significantly higher efficacy concerning the occurrence of breakthrough infections when compared with the AstraZeneca vaccine. Overall, our study reflected the immune status of a sample of vaccinated adults in North Lebanon. Further studies on a larger scale are needed at the national level to follow the immune response after vaccination, especially after the addition of the third vaccination dose.
“…showed that the 2 viral-vector vaccines JNJ-78436735 (Ad26.COV2.S) and AstraZeneca vaccine (ChAdOx1 nCoV-19) were associated with a higher risk of breakthrough infection compared to BNT162b2 [ 35 ]. This is concordant with a study conducted in Iraq, showing that the AstraZeneca vaccine was more associated with breakthrough infections in comparison with mixed vaccines or BNT162b2 vaccines [ 36 ]. A study in the United Kingdom including a group of vaccinated index patients and unvaccinated ones, compared the probability of infection of people in contact with these 2 groups.…”
Since March 2020, the COVID-19 pandemic has swiftly propagated, triggering a competitive race among medical firms to forge vaccines that thwart the infection. Lebanon initiated its vaccination campaign on February 14, 2021. Despite numerous studies conducted to elucidate the characteristics of immune responses elicited by vaccination, the topic remains unclear. Here, we aimed to track the progression of anti-spike SARS-CoV-2 antibody titers at two-time points (T1: shortly after the second vaccination dose, T2: six months later) within a cohort of 201 adults who received Pfizer-BioNTech (BNT162b2), AstraZeneca, or Sputnik V vaccines in North Lebanon. Blood specimens were obtained from participants, and antibody titers against SARS-CoV-2 were quantified through the Elecsys-Anti-SARS-CoV-2 S assay (Roche Diagnostics, Switzerland). We used univariate analysis and multivariable logistic regression models to predict determinants influencing the decline in immune response and the occurrence of breakthrough infections among vaccinated patients. Among the 201 participants, 141 exhibited unchanging levels of antibody titers between the two sample collections, 55 displayed waning antibody titers, and only five participants demonstrated heightened antibody levels. Notably, age emerged as the sole variable significantly linked to the waning immune response. Moreover, the BNT162b2 vaccine exhibited significantly higher efficacy concerning the occurrence of breakthrough infections when compared with the AstraZeneca vaccine. Overall, our study reflected the immune status of a sample of vaccinated adults in North Lebanon. Further studies on a larger scale are needed at the national level to follow the immune response after vaccination, especially after the addition of the third vaccination dose.
“…Many studies have demonstrated the rapid decay of anti-spike antibodies elicited by vaccination ( 6 – 15 ), as well as those from SARS-CoV-2 infection ( 16 – 26 ). This is likely a factor in the high frequency of “breakthrough” infections and re-infections among vaccinees ( 27 – 32 ) and COVID-19-recovered persons ( 33 – 37 ), although variation of the spike sequence (particularly the receptor binding domain that is the main target of neutralizing antibodies) is a major contributor ( 13 , 29 , 38 – 42 ). Vaccine protection from severe illness has been more durable ( 43 – 45 ), which might be due at least in part to cellular immunity and epitope sequences being less affected by spike sequence variation than neutralizing antibodies ( 38 , 46 – 50 ).…”
IntroductionWhile antibodies raised by SARS-CoV-2 mRNA vaccines have had compromised efficacy to prevent breakthrough infections due to both limited durability and spike sequence variation, the vaccines have remained highly protective against severe illness. This protection is mediated through cellular immunity, particularly CD8+ T cells, and lasts at least a few months. Although several studies have documented rapidly waning levels of vaccine-elicited antibodies, the kinetics of T cell responses have not been well defined.MethodsInterferon (IFN)-γ enzyme-linked immunosorbent spot (ELISpot) assay and intracellular cytokine staining (ICS) were utilized to assess cellular immune responses (in isolated CD8+ T cells or whole peripheral blood mononuclear cells, PBMCs) to pooled peptides spanning spike. ELISA was performed to quantitate serum antibodies against the spike receptor binding domain (RBD). ResultsIn two persons receiving primary vaccination, tightly serially evaluated frequencies of anti-spike CD8+ T cells using ELISpot assays revealed strikingly short-lived responses, peaking after about 10 days and becoming undetectable by about 20 days after each dose. This pattern was also observed in cross-sectional analyses of persons after the first and second doses during primary vaccination with mRNA vaccines. In contrast, cross-sectional analysis of COVID-19-recovered persons using the same assay showed persisting responses in most persons through 45 days after symptom onset. Cross-sectional analysis using IFN-γ ICS of PBMCs from persons 13 to 235 days after mRNA vaccination also demonstrated undetectable CD8+ T cells against spike soon after vaccination, and extended the observation to include CD4+ T cells. However, ICS analyses of the same PBMCs after culturing with the mRNA-1273 vaccine in vitro showed CD4+ and CD8+ T cell responses that were readily detectable in most persons out to 235 days after vaccination.DiscussionOverall, we find that detection of spike-targeted responses from mRNA vaccines using typical IFN-γ assays is remarkably transient, which may be a function of the mRNA vaccine platform and an intrinsic property of the spike protein as an immune target. However, robust memory, as demonstrated by capacity for rapid expansion of T cells responding to spike, is maintained at least several months after vaccination. This is consistent with the clinical observation of vaccine protection from severe illness lasting months. The level of such memory responsiveness required for clinical protection remains to be defined.
“…The effect of age on the risk of BTI in our study was the opposite of that demonstrated in risk assessment studies conducted in the pre-vaccination era. Additionally, there is some variability in terms of the incidence of BTI in studies conducted during the same period of the pandemic, depending on the prevalent SARS-CoV-2 strain and setting 37 , 38 . Figure 2 Risk for SARS-CoV-2 breakthrough infection and severe COVID-19 according to age of study participants.…”
SARS-CoV-2 vaccination is currently the mainstay in combating the COVID-19 pandemic. However, there are still people among vaccinated individuals suffering from severe forms of the disease. We conducted a retrospective cohort study based on data from nationwide e-health databases. The study included 184,132 individuals who were SARS-CoV-2 infection-naive and had received at least a primary series of COVID-19 vaccination. The incidence of BTI (breakthrough infection) was 8.03 (95% CI [confidence interval] 7.95⎼8.13/10,000 person-days), and for severe COVID-19 it was 0.093 (95% CI 0.084⎼ 0.104/10,000 person-days). The protective effect of vaccination against severe COVID-19 remained constant for up to six months, and the booster dose offered an additional pronounced benefit (hospitalization aHR 0.32, 95% CI 0.19⎼0.54). The risk of severe COVID-19 was higher among those ≥ 50 years of age (aHR [adjusted hazard ratio] 2.06, 95% CI 1.25⎼3.42) and increased constantly with every decade of life. Male sex (aHR 1.32, 95% CI 1.16⎼1.45), CCI (The Charlson Comorbidity Index) score ≥ 1 (aHR 2.09, 95% CI 1.54⎼2.83), and a range of comorbidities were associated with an increased risk of COVID-19 hospitalization. There are identifiable subgroups of COVID-19-vaccinated individuals at high risk of hospitalization due to SARS-CoV-2 infection. This information is crucial to driving vaccination programs and planning treatment strategies.
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