Mathematical modelling of COVID-19 vaccination strategies in Kyrgyzstan

Objectives: In December 2020, an unprecedented vaccination programme to deal with the COVID-19 pandemic was initiated worldwide. However, the vaccine provision is currently insufficient for most countries to vaccinate their entire eligible population, so it is essential to develop the most efficient vaccination strategies. COVID-19 disease severity and mortality vary by age, therefore age-dependent vaccination strategies must be developed. Study design and Methods: Here, we use an age-dependent SIERS (susceptible, infected, exposed, recovered, susceptible), deterministic model, to compare four hypothetical age-dependent vaccination strategies and their potential impact on the COVID-19 epidemic in Kyrgyzstan. Results: Over the short-term (until March 2022), a vaccination rollout strategy focussed on high-risk groups (aged greater than 50 years) with some vaccination among high-incidence groups (aged 20 to 49 years) may decrease symptomatic cases and COVID-19-attributable deaths. However, there will be limited impact on the estimated overall number of COVID19 cases with the relatively low coverage of high incidence groups (15 to 25% based on current vaccine availability). Vaccination plus nonpharmaceutical interventions (NPIs), such as mask-wearing and social distancing will further decrease COVID-19 incidence and mortality and may have an indirect impact on all-cause mortality. Conclusions: Our results and other evidence suggest that vaccination is most effective in flattening the epidemic curve and reducing mortality if supported by NPIs. In the short term, focussing on high-risk groups may reduce the burden on the health system and result in fewer deaths. However, the herd effect from delaying another peak may only be achieved by greater vaccination coverage in high incidence groups.

SARS-CoV-2: Emergence of New Variants and Effectiveness of Vaccines

The emergence of SARS-CoV-2 variants may cause resistance at the immunity level against current vaccines. Some emergent new variants have increased transmissibility, infectivity, hospitalization, and mortality. Since the administration of the first SARS-CoV-2 vaccine to a human in March 2020, there is an ongoing global race against SARS-CoV-2 to control the current pandemic situation. Spike (S) glycoprotein of SARS-CoV-2 is the main target for current vaccine development, which can neutralize the infection. Companies and academic institutions have developed vaccines based on the S glycoprotein, as well as its antigenic domains and epitopes, which have been proven effective in generating neutralizing antibodies. The effectiveness of SARS-CoV-2 vaccines and other therapeutics developments are limited by the new emergent variants at the global level. We have discussed the emergent variants of SARS-CoV-2 on the efficacy of developed vaccines. Presently, most of the vaccines have been tremendously effective in severe diseases. However, there are still noteworthy challenges in certifying impartial vaccines; the stories of re-infections are generating more stressful conditions, and this needs further clinical evaluation.

Running away from the jab: factors associated with COVID-19 vaccine hesitancy in Brazil

OBJECTIVE: To investigate how sociodemographic conditions, political factors, organizational confidence, and non-pharmaceutical interventions compliance affect the COVID-19 vaccine hesitancy in Brazil. METHODS: Data collection took place between November 25th, 2020 and January 11th, 2021 using a nationwide online survey. Subsequently, the researches performed a descriptive analysis on the main variables and used logistic regression models to investigate the factors associated with COVID-19 vaccine hesitancy. RESULTS: Less concern over vaccine side effects could improve the willingness to be vaccinated (probability changed by 7.7 pp; p < 0.10). The current vaccine distrust espoused by the Brazilian president is associated with vaccine hesitancy, among his voter base. Lower performance perception (“Very Bad” with 10.7 pp; p < 0.01) or higher political opposition (left-oriented) regarding the current presidency is associated with the willingness to be vaccinated. Higher compliance with non-pharmaceutical interventions (NPIs) is usually positively associated with the willingness to take the COVID-19 vaccine (+1 score to NPI compliance index is associated with higher willingness to be vaccinated by 1.4 pp, p < 0.05). CONCLUSION: Willingness to be vaccinated is strongly associated with political leaning, perceived federal government performance, vaccine side effects, and compliance with non-pharmaceutical interventions (NPIs).

SARS-CoV-2 Antibody Response is Associated with Age in Convalescent Outpatients

COVID-19 has had an unprecedented global impact on human health. Understanding the antibody memory responses to infection is one tool needed to effectively control the pandemic. Among 173 outpatients who had virologically confirmed SARS-CoV-2 infection, we evaluated serum antibody concentrations, microneutralization activity, and enumerated SARS-CoV-2 specific B cells in convalescent blood specimens. Serum antibody concentrations were variable, allowing for stratification of the cohort into high and low responders. Serum antibody concentration was associated with microneutralization activity and participant age, with participants under the age of 30 showing the lowest antibody level. Neither participant sex, the timing of blood sampling following the onset of illness, nor the number of SARS-CoV-2 spike protein specific B cells correlated with serum antibody concentration. These data suggest that young adult outpatients did not generate as robust antibody memory, compared with older adults. Further, serum antibody concentration or neutralizing activity trended but did not significantly correlate with the number of SARS-CoV-2 memory B cells. These findings have direct implications for public health policy and current vaccine efforts. Knowledge gained regarding antibody memory following infection will inform the need for vaccination in those previously infected and allow for a better approximation of population-wide protective immunity.

Current COVID-19 vaccine epidemiology and dentistry

The coronavirus disease 2019 (COVID-19) vaccine story is continuously unfolding. Since our previous COVID-19 commentaries, much new information has transpired on the subject, and here we revisit this topic, which has practical implications for all stakeholders in dentistry, as well as the public. This article, on current vaccine epidemiology, provides an account of why vaccines fail in general, and the particular concerns in relation to the new Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related ‘variants of concern’. Issues related to vaccine failure are fundamentally dichotomous in nature, appertaining either to the vaccine strain (type) per se, and/or the numerous endogenous factors of the vaccine recipient/vaccinee. Societal factors such as vaccine hesitancy and its impact on herd immunity appear to overarch the long-term goal of total or partial global suppression of SARS-CoV-2, and its eventual endemicity. CPD/Clinical Relevance: To describe the reasons for the failure of currently administered COVID-19 vaccines, particularly in relation to the advent of the SARS-CoV-2 ‘variants of concern’, and discuss implications for clinical dental practice.

Serological Humoral Immunity Following Natural Infection of Children with High Burden Gastrointestinal Viruses

Acute gastroenteritis (AGE) is a major cause of morbidity and mortality worldwide, resulting in an estimated 440,571 deaths of children under age 5 annually. Rotavirus, norovirus, and sapovirus are leading causes of childhood AGE. A successful rotavirus vaccine has reduced rotavirus hospitalizations by more than 50%. Using rotavirus as a guide, elucidating the determinants, breath, and duration of serological antibody immunity to AGE viruses, as well as host genetic factors that define susceptibility is essential for informing development of future vaccines and improving current vaccine candidates. Here, we summarize the current knowledge of disease burden and serological antibody immunity following natural infection to inform further vaccine development for these three high-burden viruses.

Cost Analysis of Current Distribution and Redesigned Distribution Systems for Vaccines in Rwanda

Background Immunization supply chain management is among the components of immunization program, making vaccines delivery possible to reach every child. Nevertheless, it has been found to be static with rapid changes linked to the introduction of new vaccines. The success of Rwanda immunization program with coverage of 94.3% was attributed to human resource and capital investment from both the Ministry of Health and its development partners. However, the current distribution system design does not contribute to self-financing of the program in the long-run considering the distribution mode and frequency applied. The cost analysis study has never been done before and is expected to address the issue of long-term sustainability of the program as it will inform the system re-design activities. Objective Assessing how much the program would save if the system is re-designed by changing distribution mode and frequency from the Central Vaccine Store to District Vaccine Stores. Methods Administrative and financial records were reviewed to determine the cost of the current vaccine distribution system to be compared to estimated cost of a proposed distribution system with reduced frequencies between Central Vaccine Store and District Vaccine Stores. Results By comparing the costs of the two systems, applying the proposed distribution model with less distribution frequencies reduced the current cost by 37%. Conclusion The findings confirm a huge opportunity of getting the current vaccine distribution costs reduced when the distribution system is redesigned, hence contributing to financial sustainability of the vaccination program. Rwanda J Med Health Sci 2021;4(2): 207-221

The Infodemic of COVID-19

While the fight against the COVID-19 pandemic remains centered around the great strides made in fields of biotechnology and epidemiology, an epidemic of misinformation and growing skepticism of the scientific community rages beneath the surface. Almost understandably so, in an unprecedented time of change riddled with fear and a sense of loss, people turn to thoughts, emotions, and behaviours that sometimes do more to impede the return to normalcy that we all crave. Reports that were particularly prevalent during the early pandemic response, including those of individuals refusing to wear masks in public spaces or anti-lockdown rallies throughout North America, only spurred further confusion and divisive sentiments on both sides [1]. While these events may point towards a lack of clear communication and mixed messaging from authority figures in the early response, a culture of inherent skepticism, particularly on social media, continues to be pervasive. With hopes of a global re-opening riding on the current vaccine rollout, widespread acceptance of the COVID-19 vaccines remains essential to achieving herd immunity and ultimately curbing the spread of the virus. However, marginalized and underrepresented groups in North America that have been most heavily affected by the pandemic are also often those who are most distrustful of the medical system [2,3].