Post-vaccination Surveillance Research Articles

Development and Evaluation of an Indirect Enzyme-Linked Immunosorbent Assay for Detection of Foot-and-Mouth Disease Virus Nonstructural Protein Antibody using a Chemically Synthesized 2B Peptide as Antigen

Forty peptides were synthesized corresponding to hydrophilic clusters of amino acids within the sequences of foot-and-mouth disease virus (FMDV) nonstructural proteins (NSP). Six peptides were studied in more detail and the most promising, a 2B peptide, was evaluated in enzyme-linked immunosorbent assay (ELISA) using sera from naive, vaccinated, and vaccinated-and-challenged cattle as well as bovine sera from field outbreaks. The performance of the new NSP peptide ELISA was compared to that of 4 commercial NSP ELISA kits. Antibody to 2B was detectable from the end of the first week to the second week after infection in most of the nonvaccinated animals and by the second to third week in vaccinated-and-challenged animals. The sensitivity of the 2B peptide ELISA was comparable to the 3ABC Ceditest (Ceditest FMDV-NS, Cedi Diagnostics B.V.; Chung et al., 2002). With some modification and further validation, this 2B test could be useful as a screening or conformational NSP test in postvaccination surveillance for FMD.

Secretory IgA as an indicator of oro-pharyngeal foot-and-mouth disease virus replication and as a tool for post vaccination surveillance

A serotype-specific ELISA was developed to detect foot-and-mouth disease virus (FMDV) specific IgA antibody in the saliva of cattle, and the method was evaluated for its feasibility in detecting serotype O FMDV carrier animals, particularly amongst vaccinated cattle that had subsequently become sub-clinically infected. For this purpose, saliva samples were collected from naïve cattle ( n = 173), FMDV challenged cattle ( n = 10), FMDV vaccinated cattle ( n = 40) and FMDV vaccinated-and-challenged cattle ( n = 40). A subset of 29 cattle was sampled for 105–168 days after challenge. The FMDV infection status of each of the cattle was determined by virus isolation and RT-PCR tests on oesophago–pharyngeal fluids and the ability of the IgA test to detect viral infection and persistence was compared to an ELISA for the detection of serum antibodies against the 3ABC non-structural proteins of FMDV. Eleven out of twelve vaccinated cattle that were shown to be persistently infected with FMDV up to or beyond 28 days post challenge, were also detected by the IgA test on saliva. With some modification and further validation, this test could be useful in post-vaccination surveillance to help confirm the absence of sub-clinical infection in order to regain the FMD-free status of a region or country.

A short report on the highlights of world-wide development of RIX4414: a North American experience: Comparative evaluation of safety and immunogenicity of two dosages of an oral live attenuated human rotavirus vaccine (RIX4414) in infants in the United States and Canada

This randomized, double-blind trial conducted in the US and Canada was conducted to compare the safety and immunogenicity of two dosages of live attenuated oral monovalent G1 human rotavirus (HRV) vaccine administered orally at a 2-month interval concomitantly with routine childhood vaccines to healthy infants 5–15 weeks of age. No SAEs considered related to vaccine were reported. The incidence of solicited symptoms was similar among treatment groups during the 15-day post-vaccination surveillance periods. No significant difference in vaccine take after 2 doses (88.0% in high dose group and 81.5% in low dose group) was seen between vaccine groups. Two doses of either dosage level of HRV vaccine administered concurrently with routine childhood vaccines to healthy infants were well tolerated and elicited excellent vaccine takes.

Comparative Evaluation of Safety and Immunogenicity of Two Dosages of an Oral Live Attenuated Human Rotavirus Vaccine

Rotavirus is a major cause of gastroenteritis in children worldwide and is estimated to be responsible for more than 500,000 physician visits, 50,000 hospitalizations and 20 deaths in the United States each year. To compare the safety and immunogenicity of 2 dosages of a live attenuated oral monovalent G1 human rotavirus (HRV) vaccine in healthy infants. In this randomized, double blind trial conducted in the United States and Canada, 529 healthy infants 5-15 weeks of age received HRV vaccine containing either 10 or 10 focus-forming units or placebo. Two doses were administered orally at a 2-month interval concomitantly with routine childhood vaccines. Symptoms of fever, irritability/fussiness, diarrhea, vomiting, loss of appetite and cough/runny nose were solicited for 15 days postvaccination, nonserious adverse events for 43 days postvaccination and serious adverse events throughout the study. Vaccine take was defined as appearance of serum antirotavirus IgA in postimmunization sera at a titer of > or =20 units/mL or vaccine virus shedding in any stool sample collected between the first dose and 2 months after the second dose. No serious adverse events considered related to vaccine were reported. The incidence of solicited symptoms was similar among treatment groups during the 15-day postvaccination surveillance periods. No significant difference in vaccine take after 2 doses (88.0% in high dose group and 81.5% in low dose group) was seen between vaccine groups (P = 0.153). Two doses of either dosage level of HRV vaccine administered concurrently with routine childhood vaccines to healthy infants 5-15 weeks of age were well-tolerated and were highly immunogenic.

Lack of an apparent association between intussusception and wild or vaccine rotavirus infection.

Lack of an apparent association between intussusception and wild or vaccine rotavirus infection.

Results of an oral rabies vaccination program for coyotes

Objective To determine effectiveness of large-scale distribution of an oral rabies vaccine contained in a palatable bait for halting expansion of a canine rabies epizootic in coyotes (Canis latrans). Design Prospective study. Animals 98 coyotes during prevaccination surveillance and 449 coyotes and 60 other wild animals during postvaccination surveillance. Procedure A vaccinia recombinant oral rabies vaccine was inserted into an edible bait for coyotes that also contained tetracycline as a biomarker. Vaccine units were then distributed via aircraft, using automated distribution equipment and flight plans developed by incorporating global positioning system equipment. The target area was along the northern edge of an area that had an epizootic of canine rabies. This area was identified through previously conducted epidemiologic surveillance of rabies cases. During postvaccination surveillance, dental specimens were examined for biomarker evidence of bait acceptance, and serum samples were analyzed for rabies neutralizing antibodies. Results Samples from 449 coyotes were obtained during postvaccination surveillance. Seroconversion was detected in 39 of 96 (40.6%) coyotes that had evidence of tetracycline biomarker. Additionally, the number of rabies cases in the target area decreased, and expansion of the epizootic area ceased. Clinical Implications Mass distribution of an oral rabies vaccine in a palatable bait is an effective means to halt expansion of a rabies epizootic involving coyotes. (J Am Vet Med Assoc 1998; 212:498-502)