Planning risk mitigation

Choose barriers, PPE, vaccination, and sanitation that lower a pathogen's likelihood or severity to reduce overall risk.

Builds on (2 levels back)inferred · high confidence

Risk = likelihood x severity: To plan mitigation you must first understand that risk has two factors, since a measure works by lowering one of them.
Routes of transmission: Choosing the right barrier depends on how the pathogen spreads, so you need to know transmission routes.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

Mitigation reduces risk by lowering likelihood (barriers, PPE, isolation, sanitation) or severity (vaccination, early treatment). Match the measure to the bigger factor.

Step 1: Sort measures by target

Likelihood-lowering measures keep infection from happening: PPE, isolation, sanitation, and barriers. Severity-lowering measures make infection less harmful if it happens: vaccination and early treatment.

Step 2: Target the bigger factor

If a pathogen spreads very easily, attack likelihood first. If a pathogen is rare but devastating, lowering severity matters more.

Step 3: Watch the trap

A measure that does not touch either factor does not reduce risk, no matter how reasonable it sounds.

Practice

Using Risk = likelihood x severity, a pathogen scores likelihood 3 and severity 3 (data shown). A vaccine lowers its severity to 1. What is the new risk score?

Reviewed

Factor	Before	After vaccine
Likelihood (1-3)	3	3
Severity (1-3)	3	1

Show the worked solution ▾

Answer: C. 3

Step 1: Write the formula: Risk = likelihood x severity.
Step 2: Use the after-vaccine values: Likelihood is still 3; severity is now 1.
Step 3: Multiply: 3 x 1 = 3, so the new risk score is 3.

Why it's right: The vaccine lowers severity to 1 while likelihood stays 3, so the new risk is 3 x 1 = 3.

Why the others miss:

A: 9 is the original score (3 x 3) before the vaccine.
B: 6 does not come from multiplying the after values 3 and 1.
D: 1 would require likelihood to also drop to 1, but the vaccine only changed severity.

Aligned to HBS 3.3: mitigation lowers a risk factor · reading level ~grade 9

Where you'd see this

A flu campaign accepts that the flu still spreads but vaccinates to cut how severe each case is.

Careers that use this

Immunization Program Coordinator: Plans vaccination to lower the severity factor for pathogens that are hard to stop from spreading.

Video library

Watch: Planning risk mitigation

Antibiotics, Antivirals, and Vaccines

Amoeba Sisters · ~9 min

Guided notes

Fill these in as you work through the lesson.

Big idea: Mitigation lowers risk by reducing likelihood (barriers, PPE, sanitation, isolation) or by reducing severity (vaccination, early treatment), and the best plan targets the bigger factor.

Key terms: write the meaning

Mitigation (steps that lower risk):
PPE (gear you wear):
Vaccination (primes the immune system):
Sanitation (removing pathogens from surfaces):

The rule

A mitigation measure reduces risk by lowering either the of infection or the of the illness if it happens.

Check yourself

Which mitigation measures mainly lower likelihood, and which mainly lower severity?
Why is a mask the right barrier for an airborne pathogen but not the key control for a bloodborne one?
If a pathogen is already easy to catch, would you focus mitigation on likelihood or severity first?

Work one example

An airborne pathogen has high likelihood. Pick two measures (such as masks and ventilation) and explain whether each lowers likelihood or severity, and why that reduces overall risk.