Week 7 - Vaccine Effectiveness and Policy, Coronaviruses and Other Respiratory Viruses

Question 1

How do we monitor Vaccine Effectiveness (VE) over time by risk group, outcome, and product?

Answer 1

Risk group x Outcome x Product

*by time since vaccination and variant

Question 2

What are the 2023-2024 recommendations for mRNA COVID-19 vaccines?

Answer 2

Unvaccinated:
6mo-4yrs: 2 doses Moderna or 3 doses Pfizer

> = 5 years: 1 dose Moderna or 1 dose Pfizer

Previously Vaccinated:
>= 6 months: 1 dose Moderna or 1 dose Pfizer

Question 3

Define Absolute VE

Answer 3

Compare frequency of health outcomes in vaccinated and unvaccinated people

ex: compare outcomes in people vaccinated with bivalent booster vs. no vaccine at all

• More interpretable

Question 4

Define Relative VE

Answer 4

Compare frequency of health outcomes in people who received one type of vaccine to people who received different vaccine, or compare people who received more vaccine doses that those who received fewer

ex: compare outcomes in people vaccinated with updated bivalent booster vs. monovalent vaccine only

• Harder to interpret, but helpful in policy decisions
• Helps show what additional protection is provided by _____

Question 5

What are some pros and cons of test negative design?

Answer 5

• Reduce bias from health care seeking behavior
• Efficient use of an existing surveillance system
• Dependent on sensitivity and specificity of diagnostic testing

Question 6

Key conclusions of waning bivalent vaccine effectiveness

Answer 6

1. VE waning against hospitalizations and ED/UC, more sustained protection against critical illness
2. Patterns similar across age groups, but low uptake of bivalent doses in younger age groups
3. Persons immunocompromised may reduce protection after COVID-19 vaccination
4. VE findings should be interpreted as incremental benefit provided by COVID-19 vaccination in a population with high prevalence of infection induced immunity

Question 7

What are the two new tools to protect babies from severe RSV illness?

Answer 7

1. maternal RSV vaccine
2. Nirsevimab