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DHS S&T Research & Development

Response to SARS-CoV-2 / COVID-19 

UNDERSTANDING TRANSMISSION TO 

CONTROL THE SPREAD 

Efforts to control the spread of the SARS-CoV-2 rely on 

the virus’ ability to survive in the air and on surfaces. S&T 

is executing high-impact projects to help answer critical 

questions about the SARS-CoV-2 virus, including: 

 How stable is the virus in different conditions?

 How effective are different decontamination

products on surfaces?

 How can we best clean personal protective

equipment (PPE) and verify functionality?

S&T EFFORTS TO ANSWER CRITICAL 

QUESTIONS 

Master Question List 

A team of dedicated experts reviews all available 

information on the SARS-CoV-2 virus and condenses it 

into a concise format to aid decision makers and the 

public. This Master Question List (MQL) is updated 

weekly and available to the public: 

(https://www.dhs.gov/publication/st-master-question-listcovid-19). The MQL features information about virus 

spread, disease progression, effectiveness of treatments, 

decontamination methods, and more. 

Laboratory Research 

S&T provides DHS Components and stakeholders highconfidence guidance on SARS-CoV-2 through rapidlyexecuted applied-science studies and risk assessments 

to inform the operational response. Building on 

experience gained through response to the 2015 Ebola 

outbreak, S&T is executing laboratory studies at the 

National Biodefense Analysis and Countermeasures 

Center (NBACC) and with other qualified performers to 

produce informative data on SARS-CoV-2. 

Research Collaborations 

S&T is collaborating with domestic and international 

partners to address critical aspects of virus stability and 

decontamination, leveraging each laboratory’s strengths. 

Technology Scouting 

To support DHS Component requests, S&T’s Technology 

Scouting and Transition group is investigating different 

technologies for use in disinfecting surfaces and testing 

for the virus in humans. 

S&T LABORATORY RESEARCH IS AT THE 

FOREFRONT OF THE COVID-19 FIGHT 

S&T is currently executing SARS-CoV-2 studies at the 

NBACC laboratory facility. These studies are focused on 

answering the following questions: 

 How long can SARS-CoV-2 survive on commonly

used surfaces (e.g., stainless steel, nitrile, plastic) at

different temperature, humidity, and solar levels?

 How long can SARS-CoV-2 survive in simulated

human saliva droplets and respiratory fluids on

surfaces?

 How long can SARS-CoV-2 survive in the air?

 How effective are various disinfectants at eliminating

the SARS-CoV-2 virus?

NBACC EMERGING RESULTS (AS OF 4/21/20) 

Although studies are ongoing, preliminary NBACC results 

have provided critical insight to SARS-CoV-2 surface 

stability. Key findings include: 

1. Solar radiation rapidly reduces virus stability on

outdoor surfaces. Testing of virus decay in droplets

of simulated saliva on a stainless steel surface was

conducted at several different intensities of artificial

sunlight. Sunlight intensity ranged from darkness to

“full” sunlight, which is equivalent to the intensity and

composition of unobstructed sunlight at noon at

ground level in the MidAtlantic Region on the first day

of summer. The amount of time it takes for infectious

virus to be reduced by half (half-life) in a droplet of

simulated saliva on stainless steel at full solar intensity

was approximately 2 minutes at room temperature.

• Operational Relevance: This data suggests that

outdoor surfaces exposed to direct sunlight are at

lower risk for virus transmission.

04-27-20

Contact Us: hactechnologycenter@hq.dhs.gov scitech.dhs.gov dhsscitech
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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DHS S&T Research & Development

Response to SARS-CoV-2 / COVID-19 

2. Higher humidity may reduce virus survival. When

in saliva droplets, the virus is most stable at lower 

humidity.

• Operational Relevance: This indicates that the virus

is more likely to be stable and persist in areas of

lower humidity. Increasing humidity levels may

speed virus decay.

3. The virus dies faster at higher temperatures. The

virus is less stable in saliva droplets on surfaces than

in culture media and dies faster in saliva droplets at

higher temperatures.

• Operational Relevance: Increased temperatures

may help kill the virus and reduce transmission.

4. Bleach & Isopropyl Alcohol (IPA) are effective

decontamination solutions. Diluted bleach (1 cup in

1 gallon water) was effective in reducing virus

infectivity at least >99.9% in saliva droplets after 5

minutes on a stainless-steel surface. 70% IPA killed >

99.9% virus in a wet droplet of saliva and >98.1%virus 

was inactivated on stainless steel after just

30 seconds.

• Operational Relevance: Reinforces the

effectiveness of these EPA recommended

disinfectants for use by DHS and other entities to

clean and disinfect facilities.

5. Virus stability in saliva is not dependent on droplet

size. There is no statistical difference in half-life as a

function of droplet size in saliva.

• Operational Relevance: Surface stability data is

applicable to a broad range of droplets generated

by infected individuals (e.g., talking, coughing,

medical procedures).

NBACC NEXT STEPS 

In the coming weeks, NBACC will continue to execute 

laboratory research to refine and expand results. 

Anticipated gains in SARS-CoV-2 information include: 

 Additional survival data on commonly used surfaces

(e.g., stainless steel, nitrile, plastic) at different

temperatures and humidity levels

 Aerosol survival data for indoor and outdoor

conditions, including the effect of temperature,

humidity, and sunlight on virus inactivation

 Effectiveness of other disinfectants to kill the virus in

simulated saliva droplets and respiratory fluids on

surfaces

OTHER LABORATORY RESEARCH 

S&T is also initiating studies to understand: 

 Effectiveness of different decontamination methods for

Personal Protective Equipment (PPE) reuse, such as

N95 masks

 Low-tech options to support PPE reuse

 SARS-CoV-2 survival in human waste streams

 SARS-CoV-2 exposure risks during stages of infection

and resulting contamination levels on PPE

IMPACTS FOR DHS AND THE HOMELAND 

S&T efforts, such as the Probabilistic Analysis of 

National Threats Hazards and Risks program, are 

essential to producing critical information that will help 

federal leaders, public health officials, and front-line 

operators make informed decisions about the guidance, 

types of equipment, and protocols needed to combat the 

spread of SARS-CoV-2. 

S&T efforts are helping decision makers extend the 

lifespan of PPE available to healthcare workers by 

providing scientifically-backed methods to decontaminate 

and re-use PPE equipment such as masks. 

Additionally, lab results generated by S&T can improve 

accuracy of public health modeling predictions for 

potential spread (illnesses/deaths) and improve 

understanding of the impact that specific interventions 

(social distancing, individual PPE, etc.) may have on 

combatting the pandemic. 

04-27-20

Contact Us: hactechnologycenter@hq.dhs.gov scitech.dhs.gov dhsscitech