Developments in Rabies Vaccines: The Path Traversed from Pasteur to the Modern Era of Immunization

Seroepidemiological survey to cell culture rabies vaccines (CCRV) in Brazil

Rabies is a contagious viral disease that can be easily transmitted by the saliva and brain/nervous system tissues of the infected animals, causing severe and fatal encephalitis in both animals and humans. Vaccination campaigns are crucial to combat and prevent rabies's spread in dogs and humans. The Modified Fuenzalida & Palicios vaccines have been widely used since the 70s and have proven effective in producing a solid serological response. Since 2008, the Brazilian Ministry of Health has introduced a Cell Culture Rabies Vaccine (CCRV) for all dog mass vaccination campaigns in Brazil. However, to date, there is limited evidence on the immunologic response of dogs to this type of vaccine in field conditions. The present study evaluated the serological response in dogs vaccinated with CCRV from blood samples of 724 dogs using the Simplified Fluorescence Inhibition Microtest - SFIMT. Dogs with a titer equal to 0.5 IU/mL or above were considered seropositive. The results revealed that 59.12% (428/724) of all dogs tested and 48.49% (32/66) of primo-vaccinated animals were seropositive. The percentage of seronegative animals was higher than seropositive for animals that received a single dose during their life (p < 0.05). The opposite was observed in animals with five or more doses. The results of this study demonstrated that the CCRV vaccines elicit a satisfactory immunological response in field conditions and can constitute an essential population-level preventive strategy as part of annual canine rabies vaccination campaigns. Although its effectiveness has been studied, there is limited evidence of its immunological response in dogs under field conditions. This paper evaluates the serological response to CCRV in dogs vaccinated during mass vaccination campaigns from 2012 to 2017.

Protective Activity of Inactivated Rabies Vaccine Using Flagellin-Based Adjuvant

Rabies is a zoonotic disease with high lethality. Most human deaths are associated with the bites received from dogs and cats. Vaccination is the most effective method of preventing rabies disease in both animals and humans. In this study, the ability of an adjuvant based on recombinant Salmonella typhimurium flagellin to increase protective activity of the inactivated rabies vaccine in mice was evaluated. A series of inactivated dry culture vaccine for dogs and cats "Rabikan" (strain Shchelkovo-51) with addition of an adjuvant at various dilutions were used. The control preparation was a similar series of inactivated dry culture vaccine without an adjuvant. Protective activity of the vaccine preparations was evaluated by the NIH potency test, which is the most widely used and internationally recommended method for testing effectiveness of the inactivated rabies vaccines. The value of specific activity of the tested rabies vaccine when co-administered with the adjuvant was significantly higher (48.69 IU/ml) than that of the vaccine without the adjuvant (3.75 IU/ml). Thus, recombinant flagellin could be considered as an effective adjuvant in the composition of future vaccine preparations against rabies virus.

Tracking lethal threat: in-depth review of rabies

An infectious disease known as rabies (family Rhabdoviridae, genus Lyssavirus) causes severe damage to mammals' central nervous systems (CNS). This illness has been around for a very long time. The majority of human cases of rabies take place in underdeveloped regions of Africa and Asia. Following viral transmission, the Rhabdovirus enters the peripheral nervous system and proceeds to the CNS, where it targets the encephalon and produces encephalomyelitis. Postbite prophylaxis requires laboratory confirmation of rabies in both people and animals. All warm-blooded animals can transmit the Lyssavirus infection, while the virus can also develop in the cells of cold-blooded animals. In the 21st century, more than 3 billion people are in danger of contracting the rabies virus in more than 100 different nations, resulting in an annual death toll of 50,000-59,000. There are three important elements in handling rabies disease in post exposure prophylaxis (PEP), namely wound care, administration of anti-rabies serum, and anti-rabies vaccine. Social costs include death, lost productivity as a result of early death, illness as a result of vaccination side effects, and the psychological toll that exposure to these deadly diseases has on people. Humans are most frequently exposed to canine rabies, especially youngsters and the poor, and there are few resources available to treat or prevent exposure, making prevention of human rabies challenging.