Biocontainment Shower Protocols Not One-Size-Fits-All

Biocontainment Shower Protocols Not One-Size-Fits-All

July 14, 2026

Key Points:

• A new study showed that hair style, type and products can have an impact on the effectiveness of personal decontamination procedures, such as shower-out protocols.
• Researchers discovered that all shampoos used in the study inactivated the enveloped virus, but only 1 fully deactivated the non-enveloped virus. Cowashes and leave-in conditioners showed little to no antiviral effect.
• Showering with water alone for 2 minutes was often sufficient in removing non-enveloped virus particles from hair, but this efficiency varied, depending on hair structure and product used.

Washington, D.C.-A new study reveals that hair can influence the effectiveness of personal decontamination procedures at biocontainment facilities. It suggests that a minimum standardized shower time may be necessary for effective removal of non-enveloped viruses and emphasizes the importance of considering hair type and style when designing evidence-based shower-out protocols for biosafety and biosecurity policies. The study is reported in Microbiology Spectrum, an ASM journal.

Prior to this study, evidence gaps were identified in biosafety and biosecurity practices. Specifically, research was needed to evaluate the need and efficacy of an exit shower from biocontainment facilities.

"The last relevant study was published in 1967," said Maria Cajimat, Ph.D., a study author and research scientist in the Galveston National Laboratory at The University of Texas Medical Branch (UTMB). "We conducted this study to better understand how effectively different hair products and showering practices can inactivate and/or remove viruses from hair. This is particularly important for personnel working in high-containment laboratories, where proper personal decontamination is essential to prevent the transport and transmission of pathogens to the outside environment, including to other people and animals."

To conduct their study, the researchers simulated real-life decontamination practices in the laboratory and used surrogate viruses (genetically closely related viruses that can cause mild disease or do not cause disease in humans/animals) so they could conduct the study at low containment.

The researchers tested a range of common hair products used by personnel working in high-containment facilities to see whether they could inactivate the enveloped Hazara virus and the non-enveloped Bovine Rhinitis B virus. Enveloped viruses are generally more sensitive to detergents and disinfectants due to the lipid composition of their membrane coats, whereas non-enveloped viruses are more resistant to common disinfectants due to the absence of lipid coat. The researchers also evaluated whether showering physically removed non-enveloped viruses from hair.

"First, to test if different hair products could act as disinfectant, we mixed virus with different hair product suspensions. We used this suspension to infect mammalian cells, and after 7 days we checked the cells for the presence of viruses that survived the treatment with hair products. If the hair products inactivate the virus, cells will survive the infection," Cajimat explained.

Second, to mimic the shower after exit from a laboratory, they used mannequin heads with different hair styles and types, synthetic and human hair, straight, curly/kinky and twisted in locs and braids (i.e., bound hairstyle) to represent the diversity of personnel hair. They exposed the hair to virus and evaluated how washing by showering with water alone or with different hair products effectively removed viral particles. They then measured how much virus remained after washing by sampling hair strands cut from 3 different areas of the mannequin head and used these samples to infect cells. Infection was monitored visually by assessing viral cytopathic effects (i.e., cell death caused by the virus).

The results of the first part of the study, as expected, show that all shampoos inactivated the enveloped virus. However, only 1 out of 4 shampoos tested fully inactivated the more resistant non-enveloped virus. Hair products with low or no detergent activity, such as co-washes and leave-in conditioners, showed little or no antiviral effect against both viruses.

Moreover, they found that showering with water alone for 2 minutes was often sufficient to remove non-enveloped viral particles from most hair types and styles. However, removal efficiency varied, with some exceptions observed depending on hair structure and product used, particularly in highly structured styles such as dense synthetic braids.

"Our findings suggest that current shower-out procedures can be optimized, particularly with respect to hair types and hair products used," said lead study author Anastasia Accoti, Ph.D., a research scientist in the Galveston National Laboratory at UTMB. "Both hair type and hair products can influence how effectively viruses are removed during washing or showering. This indicates that standard 'one-size-fits-all' shower protocols may not be optimal. Factors such as rinsing time, massaging technique and product selection may need to be adjusted or tailored to improve decontamination efficiency."