Measles Resurgence - Michael Mina

Why is measles resurging?

Decreasing vaccination rates

Why is measles biology important now?

To explain long-term immune effects and justify vaccination

Why have vaccines always been politically controversial?

Given to healthy people
Given to babies
Mandated public health intervention

Why does measles require a large population to spread?

It exhausts susceptible hosts in small/rural populations

How does age affect measles severity?

Older age → more severe disease

What happened to overall mortality after measles vaccination rollout (1963)?

Deaths from other infections also decreased

Two hypotheses for reduced non-measles mortality after vaccination?

1. Vaccine boosts immune system non-specifically

   1. Natural measles damages immune system

What receptor does measles use to enter cells?

CD150

Old assumption about immune recovery after measles?

Immune system returns to normal after a few weeks

What is the new understanding of measles’ immune effect?

Long-term immune damage

What is “immune amnesia”

Loss of previously acquired immune memory after measles infection

What happens to antibody levels after measles infection?

Significant loss of antibodies to other pathogens

How does measles affect the immune repertoire?

Deletes large portions of antibody memory

Does measles provide strong immunity to itself?

Yes

What is the trade-off of natural measles infection?

Strong measles immunity
Loss of protection against other diseases

How long can measles influence non-measles deaths?

Up to ~27 months afterward

What population factor predicts measles outbreaks?

birth rate

Why is rebuilding immunity after measles risky?

Requires re-exposure to infections
Increases morbidity and mortality

What did Dutch pre- and post- measles blood studies show?

Vaccinated kids → antibody increase
Measles-infected kids → major antibody loss

Can antibody levels normally drop that dramatically?

No — even chemotherapy doesn’t usually cause that level of loss

Overall conclusion about measles infection?

Causes long-term immune damage
Increases risk of other infections for years