At last some concrete data:
Quote:
CDC Identifies Small Group of Covid-19 Infections Among Fully Vaccinated Patients
By Robbie Whelan
April 15, 2021 8:37 am ET
The U.S. Centers for Disease Control and Prevention has identified a small cohort of approximately 5,800 cases of Covid-19 infection among more than 66 million Americans who have completed a full course of vaccination.
These so-called breakthrough cases, which are defined as positive Covid-19 test results received at least two weeks after patients receive their final vaccine dose, represent 0.008% of the fully vaccinated population.
Officials said such cases are in line with expectations because the approved vaccines in the U.S. are highly effective but not 100% foolproof. They are a reminder that even vaccinated people are at risk and should continue to take precautions such as masking and social distancing in many circumstances . . . .
The Wall Street Journal contacted health departments in all 50 states and the District of Columbia to ask how many breakthrough cases had been identified. Twenty-three states responded, reporting a total of 4,172 breakthrough cases.
One area of focus for the CDC is conducting genomic sequencing on respiratory samples from patients with breakthrough cases, so that the agency can track genetic variants of the coronavirus for clues as to how they interact with the vaccines. Public-health officials are studying whether certain mutations of the coronavirus are more resistant to vaccine-based immunity.
The CDC has established a database to record details of each breakthrough case, including patient demographics, geographic location, time since vaccination, vaccine type and virus lineage . . . .
Of the breakthrough cases identified by the CDC, more than 40% occurred in people older than 60, while 65% of the cases were in female patients, according to Tom Clark, leader of the vaccine evaluation team at the federal agency. The CDC found that 29% of breakthrough infections were asymptomatic and 7% of patients experiencing a breakthrough infection were hospitalized. So far, 74 people have died after experiencing breakthrough infections. The agency is expected to publish some of these findings next week . . . .
Currently there are five variants of the SARS-CoV-2 virus circulating in the U.S., several of which scientists believe to be more easily transmissible among humans than the originally identified version of the virus. Public-health officials believe that studying breakthrough cases will help them better understand how variants work . . . .
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https://www.wsj.com/articles/cdc-ide...d=hp_lead_pos7
A few comments:
- The overall number and percentage of breakthrough cases isn't surprising and, in fact, is reassuring. Even more reassuring to me is that the CDC seems to be on top of genomic sequencing of breakthrough cases to determine whether they are viruses against which the vaccines are effective most of the time or possibly new mutant strains against which the vaccine my have significant lesser effectiveness. So far, that hasn't been the case.
- What is a bit surprising to me although maybe it shouldn't be is that 74 breakthrough cases have died. Recall that in phase 3 testing with the Moderna and Pfizer vaccines, there were NO deaths among vaccinated individuals.
- Finally, 40% of the breakthrough cases were in people older than 60 whereas (by subtraction) 60% were younger than 60. Given the preponderance of older people among those so far vaccinated, this is a bit surprising. One possibility is that it's because the younger people who were vaccinated early were largely at higher than typical risk--health care workers and so on. In any case, this would seem to confirm that the vaccine works at least as well in older people as in younger in spite of their supposedly weaker immune systems.