Following recent confirmation by the US Center for Disease Control and Prevention (CDC) and the World Health Organisation (WHO) that the Zika virus is a cause of microcephaly and Guillain-Barré syndrome, there is a renewed urgency to find solutions amid fears that the current Zika outbreak in the Americas could reach epidemic levels.

In its latest epidemiology alert, the WHO reports that as of 6 April, 33 countries and territories in the Americas reported mosquito-borne transmission of the virus and three reported cases of sexual transmission. The data indicates an acceleration in the spread of the Zika virus across South and Central America from October 2015 onwards.

European nations have also reported several cases, involving people who have recently returned from infected South American areas. A heightened state of vigilance is in place in Europe and the United States to screen for ZIKV in travellers with fever returning from ZIKV-endemic countries.

Zika virus is known to be transmitted by daytime-active Aedes mosquitoes. However, some research has indicated the possible transmission of Zika through sexual intercourse; the Pan American Health Organization (PAHO), however, has deemed the evidence inconclusive. The PAHO has also said Zika can be transmitted through blood, but that such transmission is rare.

The epicentre of the current Zika’s outbreak is in Brazil, Latin America’s largest economy. Brazil’s tropical climate, fragile public health system, and relatively poor sanitation have facilitated the spread of the virus.

The situation in Brazil has been compounded by a surge in cases of microcephaly. Between 22 October 2015 and 2 April 2016 a total of 6906 cases of microcephaly and/or central nervous system (CNS) malformation were reported by Brazil. This contrasts with the period from 2001 to 2014, when an average of 163 microcephaly cases was recorded nationwide per year.

Similarly, Colombia reported at the end of March 50 live births with microcephaly between 4 January 2016 and 20 March 2016. This number represents an increase compared to the historical annual average expected (140 per year). Of the 50 cases registered, 18 were discarded.

R&D efforts for a candidate vaccine

After the WHO declared Zika to be a public health emergency of international concern (PHEIC), global health institutions such as the PAHO, as well as the US and the EU, announced new emergency funding for Zika virus control, research and development.

The European Directorate-General for Research and Innovation allocated USD11.2 million for emergency operations and scientific research towards tackling Zika in Latin America. Furthermore, last week the US government confirmed that it would be diverting funds of USD589 million, which had originally been earmarked for fighting the Ebola virus, to tackle Zika instead. However, this falls far short of the USD1.8 billion in emergency funds that the Obama administration has been seeking from Congress.

Additionally, the US House of Representatives has approved a bill that would allow the US FDA to include treatments for the Zika virus within its priority-review voucher programme. This programme means that a company that develops a Zika vaccine could potentially benefit from a voucher that would expedite the FDA’s approval process for one of the company’s more lucrative drugs.

The pharmaceutical industry has also responded proactively with several major pharmaceutical firms such as GlaxoSmithKline (GSK; UK), Sanofi (France), and the US-based pharma companies Pfizer, Johnson & Johnson (J&J), and Merck & Co currently studying the feasibility of using their existing vaccine technology for researching and developing a Zika vaccine.

The WHO reported on 14 February that 15 companies or institutions were conducting research to develop a potential Zika vaccine, and affirmed that Indian firm Bharat Biotech and the US’s National Institutes of Health (NIH) appeared to be the most advanced in this regard – although it will take at least 18 months for any product to be ready for clinical trials.

At the end of February 2016, Inovio Pharmaceuticals (US) announced that preclinical testing of its synthetic vaccine for the Zika virus induced robust and durable immune responses, demonstrating the potential for a viable vaccine to prevent and treat Zika infection. Inovio is developing its Zika vaccine with the South Korea-based biopharmaceutical company GeneOne Life Sciences, and academic collaborators.

In Brazil, the São Paulo-based Butantan Institute is leading the research charge on Zika, and has agreed to speed up its development time-frame from three years to 18 months. Additionally, researchers at the Federal University of Rio de Janeiro’s molecular virology laboratory have obtained the genome sequence of the Zika virus.

Joint efforts are also underway to fast-track the registration of clinical trials of candidate vaccines and the marketing authorisation of potential Zika virus treatments. In February, Brazil’s National Health Surveillance Agency (Anvisa) and the US’s NIH entered into a co-operation agreement focusing on the fast-track approval of a potential candidate vaccine. In April, Anvisa also entered into a co-operation agreement with 12 international health regulatory agencies for a similar purpose.

Unlike the case with Ebola, there is not yet a developed Zika candidate vaccine ready to go through clinical trials. Vaccine development is time-consuming, particularly in the case of biologic products that are based on complex procedures using cells.

A therapeutic treatment for controlling the current Zika outbreak in the Americas remains some way off. Phase I clinical trials, involving the administration of Zika candidate vaccines and/or therapies to a small number of healthy volunteers, are likely to begin by the end of the year, with large-scale Phase II clinical trials in infected patients taking place at the beginning of 2017, at the earliest. This means that it will take at least two years for a reliable Zika vaccine to become available on the market.

A special report in the impact of Zika on Brazil, its economy, and the coming Olympic Games is available through our World Markets Healthcare analysis co-authored with Carlos Caicedo, a Senior Principal Analyst on the IHS Country Risk team.