HMN 2026: How Biocontainment facility shower protocols are not one-size-fits-all

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 the 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.

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

“The last relevant study was published in 1967,” said Maria Cajimat, a study author and research scientist at 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 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 or 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 because of the lipid composition of their membrane coats, whereas non-enveloped viruses are more resistant to common disinfectants because they lack a lipid coat. The researchers also evaluated whether showering physically removed non-enveloped viruses from hair.

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

Second, to mimic the shower after exiting a laboratory, the researchers used mannequin heads with different hairstyles and hair types, including synthetic and human hair, as well as straight, curly/kinky, and hair twisted in locs and braids (i.e., bound hairstyle). These represented the diversity of personnel’s hair. They exposed the hair to virus and evaluated how effectively showering with water alone or with different hair products removed viral particles. They then measured how much virus remained after washing by sampling hair strands cut from three 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, showed that all shampoos inactivated the enveloped virus. However, only one of four 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, the researchers 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 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, a research scientist at 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.”

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