Guidance

Core principles relating to the biology and transmission of Nipah virus

Published 2 April 2026

Purpose 

This document outlines the current knowledge and assumptions about the biology and transmission of Nipah virus (NiV) to be used in developing an evidence-based response to cases of NiV. 

Audience 

The principles will be of use to public health professionals, NHS and other health and social care staff as well as other organisations and settings developing operational NiV guidance. 

Assumptions about transmission and biology of NiV 

The following assumptions are based on the available data and expert opinion. These assumptions will be regularly reviewed against emerging evidence and updated where appropriate. 

Transmission 

The mode of transmission of NiV is poorly evidenced but it is thought to spread through several routes, including:

• direct contact with an infected person or animal, or their body fluids
• ingestion of fruit or food products (such as date palm sap) contaminated with NiV
• contact with surfaces, materials or fomites contaminated with NiV
• human-to-human transmission, which may involve airborne, droplet or contact routes

Respiratory secretions are considered important for human-to-human transmission of NiV, and NiV RNA has been identified in the saliva of infected patients.

NiV should be assumed to be present in the respiratory tract of infected patients, therefore the standard airborne precautions including aerosol generating procedure (AGP) infection control practices should be applied in healthcare settings. A list of AGPs is available in the local country-specific national infection prevention control manuals.

NiV RNA has been detected in semen from an individual who received treatment for NiV infection, with RNA detected at day 26 following onset of illness (but not at days 42 or 59). Although the viability of NiV detected in semen remains unclear, on a precautionary basis, genital secretions (for example semen) should be considered as potentially infectious for at least 12 weeks after symptoms have resolved. This data will be reviewed as evidence emerges.

There are insufficient data to assess whether transmission of NiV can occur from an infected person before they develop symptoms (asymptomatic transmission), but this will be kept under review.

Incubation and infectious periods 

The incubation period of NiV generally ranges between 4 and 21 days, but longer incubation periods of up to 2 months have been reported.

Based on available evidence, cases are presumed infectious for up to 21 days after symptom onset.

Clinically at-risk groups 

Case fatality rates from previous outbreaks are between 40% and 75%.

There are insufficient data to assess severity in specific groups, but individuals at increased risk of infection include household members, caregivers and healthcare workers caring for individuals with NiV infection.

Virus survival 

NiV can survive for up to 3 days in some fruit juices or fruits at local ambient temperatures. It can also remain infectious for at least 7 days in date palm sap kept at 22°C. The virus has a half-life of 18 hours in the urine of fruit bats. However, it can be completely inactivated by heating at 100°C for more than 15 minutes.

Given its enveloped nature, NiV can be inactivated by detergents and sodium hypochlorite (10,000 parts per million (ppm) with 10 minutes contact time).

Past studies have indicated that other paramyxoviruses can survive on surfaces for up to 10 hours and be a source of infection for patients, healthcare workers, and hospital visitors. Animal experiments with NiV in a hamster model also showed that NiV can be transmitted through fomites. NiV specific studies have suggested a greater than 2 log reduction in viral load in 60 minutes at room temperature on non-porous polystyrene media.

There are currently limited data on transmission of NiV via contaminated objects or materials, therefore thorough environmental decontamination is recommended to reduce the risk of transmission from contaminated objects or materials.

Implications

NiV is classed as an airborne high consequence infectious disease (HCID) in the UK and therefore requires management through HCID pathways in healthcare settings. Patients who are under investigation or confirmed to have NiV infection should be isolated in an airborne infection isolation room, or a side room if an airborne infection isolation room is not available, and be placed on strict contact, droplet and airborne precautions.

Personal protective equipment (PPE)

PPE requirements for suspected and confirmed HCIDs can be found in the National infection prevention and control manual (NIPCM) for England.

Cleaning and decontamination

All waste generated during the care of suspected and confirmed NiV patients should be handled as category A waste. Linen and laundry from suspected and confirmed cases should be managed as infectious linen and laundry. Waste generated in the care of patients confirmed with NiV infection, including laboratory waste and used PPE, is considered Category A waste, and should be handled in accordance with local guidance.

Further guidance on safe management of waste is available if required.

Rooms occupied by confirmed NiV cases should be terminally cleaned followed by use of bleach-based disinfectants (all situations) and vapourised hydrogen peroxide (where possible). Given its enveloped nature, NiV can be inactivated by detergents and sodium hypochlorite (10,000 ppm with 10 minutes contact time).