More than a quarter of fully vaccinated residents of a Kentucky nursing home still contracted a rare variant of COVID-19, one of two new studies revealed by the Centers for Disease Control and Prevention (CDC).
Studies trace how the coronavirus was worn through specialized nursing facilities in Chicago and Kentucky.
In Chicago, only about four percent of infections occurred among people who had been shot.
But a rare variant in a single Kentucky facility meant that vaccines were only about 66% effective for residents and 76% for staff, well below the 94% of 95% effectiveness found in clinical trials for the Moderna and Pfizer dams, respectively.
A couple of studies point out that vaccines work well, but do not guarantee protection, especially when dangerous variants are circulating.
None of the three vaccines authorized in the United States were 100% effective in clinical trials, which means that so-called “advanced” infections are to be expected.
At a Kentucky nursing home, 18 vaccinated residents (black stripes) were infected with a rarer and more infectious Covid variant, as well as four staff members at the vaccinated nursing home (light blue).
ONLY four percent of fully vaccinated staff and (black) residents of 78 nursing homes in Chicago became infected
In Chicago, there were outbreaks of COVID-19 in 75 of 78 nursing homes between December 2020 and March 2021.
During this period, there were 627 cases of COVID-19 at the facility.
Of these, 22 were considered advanced infections, which occurred in 15 of the households. Twelve of these were residents – most of whom were 60 or older – and 10 were staff members.
This represents only about four percent of all nursing home cases during the period in Chicago, suggesting that the shootings were generally about 96 percent effective.
However, vaccination rates varied widely from residence to residence.
Some had vaccination rates as low as 18%, while 96% of residents and staff were vaccinated in others.
The Kentucky nursing home was hit by R1, a rare Covid variant that the CDC does not consider of interest or concern. It accounts for only 1.1% of infections in the US
Most people who caught coronavirus after getting vaccinated never had any symptoms (64%).
Five of them developed symptoms, but only mild ones. Two of the residents of the nursing homes were hospitalized for COVID-19 after severe infections and eventually one of them died.
In general, in Chicago, vaccines worked roughly as expected, and no one who developed an advanced infection transmitted the virus in a secondary transmission.
Even in the face of a worrying variant, vaccines were still very effective, preventing about 87 percent of infections in a Kentucky nursing home.
But the higher rate of advanced cases revealed how current and future variants could escape vaccines.
More than 90 percent of residents and just over half of the residence’s staff had been fully vaccinated against COVID-19 in March.
In total, 26 residents and 20 staff members of the facility, which housed 83 residents served by 116 employees, developed COVID-19.
Twenty-two were advanced infections in people who had had both doses of vaccines.
Genome sequencing of a virus sample revealed that a variant known as R1 was driving the outbreak.
The CDC has not considered R1 to be a variant of concern or interest, so it is not considered a significant threat.
But it does have three mutations in its peak protein, the part of the virus that allows it to break into human cells, which can make it more infectious and less affected by antibodies to coronavirus triggered by a previous infection or vaccines.
According to CDC monitoring, about 1.1 percent of all infections in the United States are caused by R1, which is slightly more than the South African variant, B3151, and slightly less than the Brazilian variant. P1.
The R1 variant affected vaccinated elderly people at the facility at an alarming rate.
More than a quarter of fully vaccinated residents were infected, as well as more than seven percent of staff members.
According to the CDC study, it is possible that four people have become infected and have developed symptoms with their second virus attacks.
The risks of developing the infection were still about three times lower for vaccinated people compared to those who were not vaccinated.
And the vaccines prevented 87 percent of staff from developing symptoms of Covid or being hospitalized for the infection and prevented 94 percent of hospitalizations among residents.
In comparison, four out of six of the residents of nursing homes who had not been vaccinated and detected coronavirus had to be hospitalized.
However, one vaccinated resident died of COVID-19, as did two who were not vaccinated.
Overall, vaccines were about 66% effective in protecting residents, who were older people with typically weaker immune responses and 76% of staff against infection.
CDC authors point out that the low vaccination rate among staff members probably allowed the dangerous variant, which had never before been identified in Kentucky, to enter and spread through the facility.