ABSTRACT
Vaccines are biological products that protect against pathogens such as bacteria and viruses by eliciting an immune response. Antigens foster the response within the vaccine, generated either naturally or synthetically. Antigens are one of several components that comprise a vaccine and aid in its classification. The type of virulence factors can influence its classification as either live or nonlive. Types of vaccines may be classified based on their main content, such as protein-polysaccharide conjugate vaccines or nucleic acid vaccines. With the essential role vaccines serve and their developmental intricacies, it is understood that there is a federal entity that oversees vaccine development. In the United States the vaccine development process is regulated by the Food and Drug Administration (FDA). The beginning stages typically involve submitting an investigational new drug application (IND) for approval. Through submitting an IND, the FDA provides vaccine developers critical information regarding factors such as trial design and quality testing. Evaluation of vaccine safety and efficacy is performed during the clinical trial period. Foreign clinical, human challenge, and pediatric clinical studies are the most common types of studies recommended by the FDA. This review discusses the details regarding the general key features of vaccines and the overall federal regulation of vaccine development. © 2023 Elsevier Inc. All rights reserved.
ABSTRACT
INTRODUCTION: 'Economic euthanasia', defined as euthanasia of pets due to financial constraints despite treatable illness, is common in veterinary emergency medicine. Gastric dilatation-volvulus (GDV) in dogs is inexpensive to diagnose and has a high survival rate with corrective, but costly, surgery. Without surgery, GDV is lethal. The proportion of dogs with GDV euthanized pre-surgery emerged as a reliable metric of economic euthanasia. If the COVID-19 pandemic aggravated economic distress in dog owners compromising their ability to afford pet healthcare, an increase in pre-surgical euthanasia in dogs with GDV would be expected. We hypothesized that in dogs with GDV, the risk of pre-surgical euthanasia during the COVID-19 pandemic increased compared to such risk before the pandemic. METHOD(S): In this case-control study, we included nonreferred dogs with GDV that presented to 11 US veterinary hospitals. Dogs were cases if they were euthanized presurgery, and controls if they underwent surgical treatment. Exposure positive dogs were those presenting during the initial surge of unemployment due to COVID-19 (March 16 - July 5 2020), exposure negative dogs were those during the same period in 2019. Univariate analyses and binary logistic regression models were developed to quantify the association between COVID-19 status (present, absent) and euthanasia risk, adjusting for the effect of known confounders. The significance level was set at p < 0.05. RESULT(S): We recorded 118 dogs with GDV over the 2 time periods, with 30% of non-exposed and 52% of exposed pets being euthanized pre-surgery (OR, 2.6;95% CI, 1.2-5.4). After adjusting for age, breed, comorbidities and recumbency, the odds of euthanasia for dogs presenting during COVID-19 were 2.7 (95% CI 1.1 to 6.3) times those of dogs presented in 2019. Old age (OR, 2.6;95% CI, 1.1 to 6.1), but no other explanatory variables, were associated with pre-surgical euthanasia. CONCLUSION(S): Our findings show that in this study population, dogs with GDV presented in the period March 16 to July 5 2020 had a greater risk of euthanasia compared with dogs presented in the same period the year before. It is our inference that economic consequences arising from the COVID-19 pandemic directly impacted on the level of veterinary care owners were able to provide for their pets.