UH medical researchers report progress in developing Zika vaccine

Vaccine candidate found effective in testing with mice and monkeys

A female Aedes aegypti mosquito in the process of acquiring a blood meal from a human host in this 2006 file photo. The Aedes aegypti mosquito is behind the large outbreaks of Zika virus in Latin America and the Caribbean. University of Hawaii medical school researchers report progress in developing a vaccine candidate for the Zika virus. -- Centers for Disease Control and Prevention / JAMES GATBANY photo via AP

While University of Hawaii medical school researchers report progress in developing a vaccine candidate for the Zika virus, Maui District Health Officer Dr. Lorrin Pang said Tuesday that if and when a vaccine is developed it should be deployed as soon as possible because of the high risk of birth defects in children of infected women.

If a vaccine were available, then “let’s do it, do it quickly,” he said.

So far, the UH vaccine candidate has been found effective protecting mice and monkeys from the Zika virus.

The vaccine proposed by scientists at the John A. Burns School of Medicine was reported in the journals Frontiers in Immunology and mSphere via the open-access journal of the American Society for Microbiology. The vaccine is a recombinant sub-unit vaccine that uses only a small part (protein) of the Zika virus, produced in insect cells.

“We believe our vaccine candidate shows much promise particularly as it showed to require only two immunizations given three weeks apart and is a potentially safer alternative to other candidates already in clinical trials,” said Dr. Axel Lehrer, an assistant professor of tropical medicine and infectious diseases.

There have been no reports of locally acquired Zika virus in Maui County, although there have been a few imported cases of people who were infected overseas, Pang said. Those cases are a concern because people infected by Zika can be bitten by mosquitoes that could then spread the disease to others. (The mosquito carriers are Aedes aegypti and Aedes albopictus, which are present in Hawaii and are the same insect species that carry dengue fever and chikungunya.)

The first imported case on Maui was reported about 18 months ago, he said. There have been no recent cases, he added.

“Worldwide, Zika has quieted down . . . for reasons unknown,” Pang said.

Showing the effectiveness of a proposed vaccine in monkeys (nonhuman primates) is an important milestone because it typically predicts the vaccine will work in humans, enabling further clinical development, the medical school reported.

A strong global push to battle the Zika virus has produced more than 30 vaccine candidates after Zika outbreaks in 2015-16 in Brazil. That outbreak was linked to the infection in some pregnant women whose newborn babies had severe birth defects. Zika is spread by the bite of infected mosquitoes and through sexual transmission.

There is no treatment or cure for the Zika virus infection, and there’s no vaccine currently approved for public use.

Pang cautioned that when pregnant women receive the eventual vaccination, following further testing, they should be watched “very carefully” for any possible side effects and toxicity. And, studies should continue to see what dosage is needed to provide protection and to confirm that the vaccine is successful in preventing the disease, he said.

Pang noted that a smallpox vaccine deployed in 2002-03 with members of the military was discontinued because it was eventually found to have a cardiac side effect.

Pang said Zika and dengue fever are tough diseases to develop vaccines for because Zika and dengue might “cross react” and a person given a Zika vaccine could get worse if he or she has dengue. Zika and dengue have similar proteins, he said.

Although the target population would be child-bearing women, it also should be considered to give the vaccine to sexually active men to prevent the spread of the disease, Pang said.

“Zika spreads quickly,” he said.

Side effects of the vaccine could include headaches, fever, allergies, paralysis or a temporary coma, he said.

The UH medical school research team included two senior graduate students who served as lead authors of the scientific research papers: Liana Medina, whose early training was directly supported by a National Institutes of Health Diversity in Health-Related Research grant, and Honolulu native Albert To.

Honolulu-based Hawai’i Biotech is a key partner in the vaccine development project, the medical school reported.

Two of Hawai’i Biotech’s scientists, Dr. Jaime Horton and David Clements, contributed to the most recent publication demonstrating vaccine efficacy in monkeys, along with collaborators from Bioqual Inc. of Rockville, Md., and the Department of Diagnostic Medicine/Pathobiology, Biosecurity Research Institute, College of Veterinary Medicine, at Kansas State University.

“The intense search for a Zika remedy since early 2016 has required us to be agile, and we believe our vaccine candidate research demonstrates that such quick-turnaround results can be achieved in academic and scientific partnerships here in Hawaii,” Lehrer said. “It is incredibly gratifying that two of the scientists we are training to be the future of biomedical science played key roles in gathering, analyzing and reporting their conclusions.”

UH medical school scientists continue to work to understand the immune responses to the vaccine. They are collaborating with UH’s Kapiolani Community College in an effort to create antibodies that can be used as treatments or for improved diagnostic tests for Zika virus. Other Zika-related research at the UH medical school focuses on understanding how Zika can hide undetected in the sex organs of men for an extended period.

Funding for the most recent Zika vaccine research was provided in part by Pacific Center for Emerging Infectious Diseases Research and the National Institute of General Medical Sciences.

According to the state Department of Health, the best ways to prevent Zika virus infection are to avoid being bitten by mosquitoes in areas infected with Zika and to avoid unprotected sex with partners who’ve traveled recently to areas with Zika. There were outbreaks of Zika in Brazil and other areas of South America in 2015. Before 2015, there were outbreaks in areas of Africa, Southeast Asia and the Pacific Islands.

The Zika virus infection during pregnancy can cause microcephaly and other severe brain defects, and it has been linked to miscarriages, stillbirths and birth defects. Common symptoms of Zika infection include fever, rash, joint pain and red eyes (conjunctivitis). Other symptoms include muscle pain and headaches. The illness is usually mild, with symptoms lasting for several days to a week.

* Brian Perry can be reached at bperry@mauinews.com.