News Bites

Are we going to have a Zika vaccine in the near future?

Zika hit the news in 2016 with an outbreak in Latin America.

 

aedes
Figure 1 Aedes species of mosquito which spreads the Zika virus via biting to take a blood meal[2]
This was not the first appearance of Zika but it was a particularly vicious one. It is spread by the Aedes species of mosquito (figure 1) and symptoms last about a week before the body clears it from its system. Many people show no symptoms but it may severely affect pregnant women leading to brain defects and microcephaly where the child is born with a small head (figure 2)[1].

 

 

 

microcephaly-measuring
Figure 2 Changes in head size in those born with microcephaly[3]
Naturally the world wanted a vaccine but as with vaccines for other diseases they can take years and millions of dollars to develop especially in the case of Zika which had had very little study before this outbreak.

Surprisingly, less than a year later, there are three possible vaccines on the horizon with other ones due to start trials by the autumn[4]. This is due to the Zika virus being a relatively easy target for vaccine design. Even with some trials already happening it may be as far away as 2020 before the vaccine is available to the public.

Only a few hundred people have received the experimental vaccines so far but from these there have been no major warning signs about safety. But only time will tell whether the pharmaceutical companies producing the vaccines will be able to make any profit from it.

 

Is there a place for a vaccine?

Some people have questioned whether by the time it is ready there will still be a need for the vaccine. Others think that it will be a long-term problem, especially with global warming and the mosquito habitat grows further north.

Immunity to Zika can develop. It regularly spreads in Asia and Africa amongst kids with women being immune by the time they come to have babies. It is possible that this will also be the case in Latin America but it will take time.

 

What is the latest?

The NIAID’s (National Institute of Allergy and Infectious Diseases) Zika vaccine will move to Phase 2 (figure 3) testing in the early part of 2017. BARDA (Biomedical Advanced Research and Development Authority, an office in the Department of Health and Human Services) has spent $43 million on this and is predicted to spend hundreds of millions to reach Phase 3.

 

vaccine
Figure 3 The stages of clinical testing[5]
Many other candidates for vaccines are awaiting commercial partners to fund the necessary trials before they can move a step closer to being licensed. Pharmaceutical companies have to make profits for their shareholders so are often hesitant to fund where they cannot guarantee a profit.

“But the point is there needs to be a partnership where there are certain diseases that are deemed so horrible that we cannot allow them to happen or continue.”

– Terry Ragon from a Boston-based research institute

 

References

[1] https://www.cdc.gov/zika/about/questions.html

[2] http://www.australianscience.com.au/health/hopeful-results-in-latest-hiv-vaccine-trial-but-many-hurdles-to-overcome-yet-3/

[3] https://www.cdc.gov/zika/hc-providers/infants-children/zika-microcephaly.html

[4] https://www.statnews.com/2016/12/05/zika-vaccine-development-market/

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