US data arrives

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