New COVID-19 Cases and Hospitalizations Among Adults, by Vaccination Status — New York, May 3–July 25, 2021
https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e1.htm?s_cid=mm7034e1_w
New study from New York
First to assess vaccine protection against coronavirus infection in delta times
Data for New York May 3 to July 25
N = 10.5 million
Modest drop in vaccine effectiveness against lab confirmed infection
May 3, 91.7%
July 25, 79.8%
But
Age adjusted effectiveness against hospitalizations
May 3, 91.9% to 95.3%
July 25, 91.9% to 95.3%
Factors
Delta up from 2% to 80%
Widespread relaxations
Implications
Currently authorized vaccines have high effectiveness against COVID-19 hospitalization,
but effectiveness against new cases appears to have declined in recent months
these findings support the implementation of a layered approach centered on vaccination, as well as other prevention strategies
Effectiveness of Pfizer-BioNTech and Moderna Vaccines in Preventing SARS-CoV-2 Infection Among Nursing Home Residents Before and During Widespread Circulation of the SARS-CoV-2 B.1.617.2 (Delta) Variant — National Healthcare Safety Network, March 1–August 1, 2021
N = 85,593 weekly reports
mRNA vaccines
https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e3.htm?s_cid=mm7034e3_w
Effectiveness against infection declined in nursing homes as delta increased
March, 75%
June, 53%
Vaccination for visitors and staff is crucial,
additional doses of COVID-19 vaccine might be considered for nursing home and long-term care facility residents
Sustained Effectiveness of Pfizer-BioNTech and Moderna Vaccines Against COVID-19 Associated Hospitalizations Among Adults — United States, March–July 2021
N = 1,129 diagnosed patients
https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e2.htm?s_cid=mm7034e2_w
Analysis of patients at 21 hospitals
After 2 doses of mRNA vaccine
Across 18 states
Substantial protection against hospitalizations
No decline in protection against hospitalization over 24 weeks
Effectiveness was steady at 86% percent
Immunocompetent adults, 90% protection
Remained constant during delta surge
At 2 to 12 weeks after second dose, 86%
At 13 to 24 weeks after second dose, 84%
CDC director Rochelle Walensky
https://www.washingtonpost.com/health/2021/08/18/covid-vaccine-effectiveness/
Examining numerous cohorts through the end of July and early August, three points are now very clear
First, vaccine-induced protection against SARS-CoV-2 infection begins to decrease over time.
Second, vaccine effectiveness against severe disease, hospitalization and death remains relatively high.
And third, vaccine effectiveness is generally decreased against the delta variant
Source