In findings that hint at other possible person-to-person Zika transmission routes, a research team from Brazil's Fiocruz Institute said they have isolated live virus from the urine and saliva of acutely ill patients in Rio de Janeiro.
In other Zika developments, the US Department of Health and Human Services (HHS) announced two efforts to support eventual immunization, one to develop a new vaccine and the other to help Brazil—the hardest-hit country—boost capacity to make vaccine.
Urine and saliva as transmission threat?
The Fiocruz Institute scientists initially announced their findings in Brazil in early February and published the full results on Jun 24 in Public Library of Science (PLoS) Neglected Tropical Diseases.
Of nine patients sampled, 6 were from a group of pregnant women with rash, and 3—2 men and 1 woman—had sought care for their Zika symptoms at a Fiocruz acute care clinic. Nine urine samples and five saliva samples were collected from the patients. Tests on the samples included reverse-transcriptase polymerase chain reaction (RT-PCR), quantitative RT-PCR, nucleic acid testing (NAT), and Vero cell inoculation.
Live virus was found in two samples from different patients, one from urine and one from saliva. For patients who submitted both types of sample, urine viral loads were higher than in saliva.
The authors said their finding in saliva seems to confirm a case report of live virus isolated from the saliva of a patient who got sick in January after returning from the Dominican Republic to Italy, reported in March in Eurosurveillance.
In April, French researchers in an early-online letter to the New England Journal of Medicine reported a sexual Zika transmission case in which they couldn't rule out the possible of saliva as one of the ways the infected man passed the virus to his female partner.
The importance of both body fluids as transmission routes isn't clear and needs more study, the authors wrote. They noted that the acidic pH of urine might restrict viral spread.
For saliva, the isolation of viable virus doesn't always prove that the virus can transmit orally, because saliva typically contains antiviral molecules and is relatively hypotonic, meaning it can lyse enveloped viruses. They said the possibility of person-to-person spread through disruptions in oral mucosa or periodontal pockets, however, should be investigated.
HHS vaccine support
- In a move designed to speed development of a Zika virus vaccine, HHS today announced that its Office of the Assistant Secretary for Preparedness and Response (ASPR) will start developing one using its Center for Innovation in Advanced Development and Manufacturing (CIADM) in Baltimore. The CIADM, led by Emergent BioSolutions, Inc., will move quickly through the steps needed to submit an investigational new drug request to the Food and Drug Administration (FDA) needed to launch clinical trials. The effort will use vaccine technology similar to methods developed to protect against similar viruses such as dengue. Funding from the Biomedical Advanced Research and Development Authority (BARDA) totaling $17.9 million over the next 30 months, with the potential of $21.9 million for additional work. The arrangement has a stipulation that BARDA can transfer the technology to other vaccine manufacturers to produce and market the Zika vaccine. HHS established three CIADMs in 2012, which bring small biotechnology companies, academic groups, and large pharmaceutical companies together to develop drugs and vaccines faster and more cost effectively.
- To help Brazil boost its capacity to produce Zika virus vaccine, HHS on Jun 24 announced that it will join the World Health Organization (WHO) and other international partners to provide funding and technical assistance to Brazil's Butantan Institute. BARDA will provide $3 million through its existing cooperative partnership agreement with the WHO. The funding can be used to buy lab and manufacturing equipment, vaccine reagents, cell lines, and other supplies that can be used to produce Zika virus vaccine. BARDA experts will also provide technical assistance on issues such as best practices for vaccine development, facility design considerations, and potential regulatory considerations.
Jun 24 PLoS Negl Trop Dis abstract
Mar 10 Eurosurveill report
Apr 13 N Engl J Med letter