How has research on the effectiveness and safety of COVID-19 vaccination been evaluated: a scope review with emphasis on CoronaVac

Introduction

The control of the COVID-19 epidemic has been focused on the development of vaccines against SARS-CoV-2. All developed vaccines have reported safety and efficacy results in preventing infection and its consequences, although the quality of evidence varies depending on the vaccine considered. Different methodological designs have been used for their evaluation, which can influence our understanding of the effects of these interventions. CoronaVac is an inactivated vaccine, and it has been assessed in various studies, including clinical trials and observational studies. Given these differences, our objective was to explore the published information to answer the question: how has the efficacy/effectiveness and safety of CoronaVac been evaluated in different studies? This is to identify potential gaps and challenges to be addressed in understanding its effect.

Methods

A scoping review was carried out following the methodology proposed by the Joanna Briggs Institute, which included studies carried out in humans as of 2020, corresponding to systematic reviews, clinical trials, analytical or descriptive observational studies, in which the effectiveness and/or safety of vaccines for COVID19 were evaluated or described. There were no age restrictions for the study participants.

Results

The efficacy/effectiveness and safety of this vaccine was assessed through 113 studies. Nineteen corresponded to experimental studies, 7 of Phase II, 5 of Phase IV, and 4 were clinical trials with random assignment. Although some clinical trials with random assignment have been carried out, these have limitations in terms of feasibility, follow-up times, and with this, the possibility of evaluating safety outcomes that occur with low frequencies. Not all studies have used homogeneous methods of analysis. Both the prevention of infection, and the prevention of outcomes such as hospitalization or death, have been valued through similar outcomes, but some through multivariate analysis of dependencies, and others through analysis that try to infer causally through different control methods of confounding.

Conclusion

Published information on the evaluation of the efficacy/effectiveness and safety of the CoronaVac is abundant. However, there are differences in terms of vaccine application schedules, population definition, outcomes evaluated, follow-up times, and safety assessment, as well as non-standardization in the reporting of results, which may hinder the generalizability of the findings. It is important to generate meetings and consensus strategies for the methods and reporting of this type of studies, which will allow to reduce the heterogeneity in their presentation and a better understanding of the effect of these vaccines.

COVID-19 mortality in two waves of the pandemic in Cali, Colombia, before and during vaccination roll-out

Objective

To describe the variation in COVID-19 mortality among residents of Cali, Colombia, in the second wave of the pandemic, before vaccines, and in the fourth wave, with vaccination roll-out in process, taking into account variables of sex, age group, comorbidities, and interval between onset of symptoms and death, and to estimate the number of deaths averted by vaccination.

Methods

A cross-sectional study of second wave and fourth wave deaths and vaccination coverage. The frequencies of attributes of deceased population in the two waves were compared, including comorbidities. Machado's method was used to calculate an estimate of the number of deaths averted in the fourth wave.

Results

There were 1 133 deaths in the second wave and 754 deaths in the fourth wave. It was calculated that approximately 3 763 deaths were averted in the fourth wave in Cali in the context of vaccination roll-out.

Conclusions

The decline in COVID-19-associated mortality observed supports the continuation of the vaccination program. Given the lack of data to explain other possible reasons for this decline, such as on the severity of novel viral variants, the limitations of the study are discussed.

[Association between oral health and cognitive decline in older Chileans]

OBJECTIVE

To identify the association between oral health and suspected cognitive impairment in older adults in Chile.

METHOD

Cross-sectional study including 1826 people ≥60 years who participated in the National Health Survey of Chile, 2016-2017. Oral health was evaluated by the number of teeth, presence of caries, use of dental prostheses, self-reported oral health, and pain and/or discomfort in the oral cavity. Cognitive impairment was assessed using the Mini-Mental State Examination (MMSE). The association was evaluated by logistic and linear regression, adjusted for sociodemographic and lifestyle variables.

RESULTS

Compared with people without suspicion of cognitive impairment, people with suspected impairment had five fewer teeth (13.4 vs. 8.5 teeth), a much higher difference in women than in men, and a higher frequency of oral pain. Edentulism and fewer teeth were associated with a higher likelihood of suspected cognitive impairment, associations that were not maintained in adjusted models. Oral pain was associated with a higher likelihood of suspected impairment even in the most adjusted model (odds ratio: 1.99; 95% confidence interval [95%CI]: 1.09-3.63). In linear models, an increase of 2% (95%CI: 0.01-0.05) in the MMSE score was observed for each additional tooth.

CONCLUSIONS

Poor oral health, particularly tooth loss and the presence of pain, was associated with cognitive impairment in older adults in Chile.

Achalasia familiar: report of a family with an autosomal dominant pattern of inherence

Esophageal achalasia is a well-known pathology with an autosomal recessive pattern of inherence described in the familiar cases. Its principal symptom is dysphagia, secondary to the poor relaxation of the lower esophageal sphincter. Chagas disease is one of the many causes involved in the development of this disease, being of great importance in our country because of the high prevalence of the vector. Various syndromes include achalasia in their symptomatology, such as the triple A syndrome or Allgrove syndrome (Addisonianism, achalasia, and alacrimia). We reported a family with a classical autosomal pattern of inherence with six affected members, four men and two women, with achalasia diagnosis as well as esophagus cancer in two of them, secondary to the disease, and no other findings.