Eradication and Vaccines Flashcards
Rinderpest
Types of polio vaccine
Must be trivalent for all 3 serotypes
Salk vaccine
1955
inactivated virus w formaldehyde (crosslinks RNA to capsid)
Sabin vaccine
1963
attenuated virus - no longer virulent
Given orally - sugar cube
The cutter incident
260 children paralysed by vaccine
Vaccine virus hadn’t been properly inactivated
How did Sabin attenuate PV?
Multiple passages through tissue culture
Virus became non-virulent due to loss of selection pressure on virulent genes
Mutations in 5’ UTR + capsid gene impaired translation and capsid assembly
Salk vaccine disadvantages
May carry live virus
cost
no intestinal immunity
Sabin vaccine disadvantages
virus shed in stools up to 3 months after
reversion to WT virulence possible