Zika Vaccine Works in Mice
First live-attenuated Zika virus vaccine candidate shows promise in mice
Source: Sue Partridge/CDC- Ft. Collins. Public domain image.
The mosquito-borne Zika virus has recently emerged as a global public health threat, causing great concern over pregnancy complications such as microcephaly and other severe birth defects. An effective vaccine that would suppress transmission and protect women and their babies from severe illness is urgently needed.
Several potential vaccines are in the works, and in a study published April 10, 2017 in the journal Nature Medicine, Chao Shan and colleagues from the University of Texas Medical Branch in Galveston, Texas reported the successful development the first live-attenuated Zika virus vaccine candidate. The mutant virus contains a 10-nucleotide deletion in the Zika virus genome, making it less virulent than the wild-type virus.
A single dose of the potent vaccine candidate elicited robust antibody and T cell responses in mice and induced immunity against an epidemic Zika virus strain, suggesting that it could protect against congenital abnormalities. Mice infected with the wild-type virus had a survival rate of only about 50 percent, whereas immunization with the vaccine candidate resulted in low viral levels in the blood and organs, limited weight loss and no mortality.
While live-attenuated vaccines generally offer fast and durable immunity, inactivated and subunit vaccines often provide enhanced safety. According to the authors, the new vaccine candidate offers a good balance between efficacy and safety, and therefore should be advanced to nonhuman primates for further development.