The CDC is coordinating with many "real world" vaccine efficacy studies utilizing frontline healthcare workers as their study participants. These arrangements include COVID-19 vaccine effectiveness evaluations but also other vaccines as a number of the studies are comprehensive and predate COVID-19 emergence.
Real-World COVID-19 Vaccine Effectiveness in Healthcare Workers
Illustration of a group of healthcare workers
A study funded and led by the Centers for Disease Control and Prevention (CDC) will evaluate how well COVID-19 vaccines prevent laboratory-confirmed, symptomatic COVID-19 in healthcare workers in the “real world,” outside of a clinical trial. The study, currently enrolling healthcare workers at 34 sites nationwide, is one of many projects analyzing the real-world protection afforded by COVID-19 vaccines.
CDC is leveraging four existing programs, each with multiple sites, to evaluate COVID-19 vaccine effectiveness among healthcare workers across 26 states:
Arctic Investigations Program (AIP) – two sites
https://www.cdc.gov/ncezid/dpei/aip/index.html
Emerging Infections Program (EIP) – 10 sites
10 state
health departments working with academic partners to conduct active population-based surveillance and special studies for several emerging infectious diseases with special emphasis on infectious diseases related to the key EIP activities.
https://www.cdc.gov/ncezid/dpei/eip/...P%20activities.
Preventing Emerging Infections through Vaccine Effectiveness Testing (Project PREVENT)external icon – 16 sites
https://medicine.uiowa.edu/content/p...revent-project
The Emerging Infections Program (EIP) is a collaboration between CDC and
Safety and Healthcare Epidemiology Prevention
Research Development (SHEPheRD Program) – six sites
https://www.cdc.gov/hai/research/safehealthcare.html
Vaccine effectiveness studies allow researchers to assess how well vaccines protect people from illness in real-world conditions. The real-world effectiveness of vaccines may be affected if vaccination process requirements, such as vaccine
storage and dosing intervals, are less strictly adhered to than they were in clinical trials. These real-world effectiveness studies may also enable researchers to evaluate vaccine effectiveness in groups not included in clinical trials, such as people with underlying
medical conditions. Additionally, they can help inform COVID-19 vaccine policy decisions made by the U.S. Advisory Committee on Immunization Practices.
COVID-19 Vaccine Effectiveness Research
Real-World COVID-19 Vaccine Effectiveness in Healthcare Workers
https://www.cdc.gov/vaccines/covid-1...protocols.html
Before the U.S.
Food and Drug Administration (FDA) determines whether to approve a vaccine or authorize a vaccine for
emergency use, clinical trials are conducted to determine vaccine efficacy.
After FDA approves a vaccine or authorizes a vaccine for
emergency use, it continues to be studied to determine how well it works under real-world conditions. CDC and other federal partners will be assessing COVID-19 vaccine effectiveness under real-world conditions.
Such evaluations will help the CDC understand if vaccines are performing as expected outside the more controlled setting of a clinical trial. As vaccine uptake increases nationally, we will also try to understand how well the vaccines:
Perform in specific subpopulations
Reduce the risk of infection (including infection without symptoms)
Protect against milder COVID-19 illness
Prevent more serious outcomes, including hospitalization
Prevent spread of illness (e.g., whether people who have been vaccinated can still spread COVID-19 to others)
Provide long-term protection (i.e., assess duration of protection)
Protect against changes in the virus (new variants)
Protect against COVID-19 when the vaccine is administered using a
single dose or when the second dose is delayed, if these dosing regimens occur under real-world conditions
Several factors can affect real-world vaccine effectiveness, including:
Population host factors (e.g., people not included in clinical trials who may respond differently to the vaccine)
Virus factors (e.g., variants)
Programmatic factors (e.g., adherence to dosing schedules or storage/handling of vaccines)
CDC will use several methods to study all of these factors, as they can all contribute different information about how a vaccine is working.