Zika vaccine development

There is currently no available and approved vaccine for the Zika virus. However, the recent outbreak of the Zika infection in South America has prompted several companies to start developing one. The World Health Organisation has reported that organisations are involved in at least 15 projects to produce the first Zika virus vaccine.

Although the Zika virus has relatively mild symptoms in humans in comparison to other viruses, it has been linked to a significant rise in the microcephaly in babies born in countries affected by a rise in infection. Microcephaly is a condition which results in defects in an infant’s brain and head development. There have also been reports of a rise in Guillain-Barré syndrome, a disease that affects the nervous system in adults who have had the virus.

Vaccines are a common way of combating mass outbreaks of viruses. Historically, German measles, small pox and typhoid have all posed serious risks to humans and vaccines have played a big role in controlling or eradicating the diseases. The Zika virus is from the flavivirus family of viruses and there are vaccines for some of the viruses in its class already such as yellow fever and Japanese encephalitis.

The body’s immune system is designed to fight off harmful pathogens that come into contact with it. Vaccines work by using a little but harmless part of the virus to trigger the body’s own immune system into fighting off a more harmful attack of the virus that it might encounter later.

How vaccines are made

A vaccine for a viral infection is made by growing the antigen, part of the disease which creates an immune response. The virus is produced in primary cells such as eggs or cell lines. The antigen is then extracted and any unwanted substances such as proteins are removed.
 

The antigen is purified. An adjuvant is then added to increase the immune response. A stabiliser may also be mixed in. After clinical trials of the vaccine, it can go into large scale production after approval by regulatory bodies.

Preparation for the Zika vaccine

The recent outbreak of Ebola has resulted in organisations being more prepared to research a new vaccine than in other times in history. Organisations now have in place processes that can help to speed the research, development and manufacturing processes along more quickly. However, companies will still need to build in time for clinical trials to ensure that the vaccine meets certain standards.

Development of the Zika vaccine

• Indian company Bharat Biotech is working on two Zika vaccines. One of them is classed as recombinant and the other is called as inactivated.
• Inovio Pharmaceuticals is working on a DNA-based vaccine for the Zika virus.
• The National Institute of Allergy and Infectious Diseases in the US is also working on a vaccine.

References

• History of vaccines on how to make a vaccine: http://www.historyofvaccines.org/content/how-vaccines-are-made
• Reuters on Bharat Biotech’s two possible vaccines for Zika: http://in.reuters.com/article/health-zika-vaccine-idINKCN0VC12U
• Reuters on Inovio Pharmaceuticals’ vaccine: http://www.reuters.com/article/us-health-zika-inovio-pharma-idUSKCN0VQ1FJ
• Wikipedia on Zika vaccine: https://en.wikipedia.org/wiki/Zika_virus#Vaccine_development