More than a quarter of the residents who were fully vaccinated in one nursing home in Kentucky still contracted a rare variant of COVID-19, showing one of the two new Centers for Disease Control and Prevention (CDC).
The studies follow how coronavirus tore through competent nursing homes in Chicago and Kentucky.
In Chicago, only about four percent of infections were among people who had their shots.
But a rare variant in a single institution in Kentucky yielded the vaccine only about 66 percent effective for residents and 76 percent effective for staff – much lower than the effectiveness of 94 percent of 95 percent used in clinical trials for shots of Moderna and Pfizer was found.
The few studies point out that vaccines work well, but that they do not provide protection, especially not where dangerous variants circulate.
None of the three vaccines authorized in the US were 100 percent effective in clinical trials, meaning so-called ‘breakthrough’ infections are to be expected.
In one nursing home in Kentucky, 18 vaccinated (black stripes) were infected with a rare, more contagious Covid variant, as well as four people vaccinated (light blue).
Only four percent of the fully vaccinated staff and residents (black) in 78 nursing homes in Chicago became infected
In Chicago, between December 2020 and March 2021, there were outbreaks of COVID-19 in 75 out of 78 nursing homes.
During that period, there were 627 cases of COVID-19 in the facilities.
Of these, 22 were considered breakthrough infections, which occurred in 15 of the homes. Twelve of these were residents – most of whom were 60 or older – and 10 staff members.
This represents only about four percent of all cases of nursing homes in the Chicago period, indicating that the shots were generally about 96 percent effective.
However, vaccination rates have varied greatly from nursing home to nursing home.
Some have the vaccination rates as low as 18 percent, while 96 percent of residents and staff have been vaccinated against others.
The nursing home in Kentucky has been hit by R1, a rare Covid variant that is not considered an interest or concern by the CDC. It represents only 1.1% of US infections
The majority of people who got coronavirus after being vaccinated never developed symptoms (64 percent).
Five of them developed symptoms, but only mild. Two of the nursing home residents were hospitalized for COVID-19 after breakthrough infections and one of them eventually died.
In general, the vaccines in Chicago were about as expected, and no one who developed a breakthrough infection transmitted the virus in a secondary transmission.
Even in light of a worrying variant, vaccines were still very effective, preventing about 87 percent of infections in a nursing home in Kentucky.
However, the higher percentage of breakthrough cases did emphasize how current and future variants of the vaccines can escape.
More than 90 percent of the residents and just over half of the staff in the nursing home were fully vaccinated against COVID-19 in March.
In total, 26 residents and 20 staff members at the facility – which houses 83 residents cared for by 116 employees – developed COVID-19.
Twenty-two of them were breakthrough infections among people who had both doses of vaccinations.
Genome sequencing of a virus sample showed that a variant known as R1 drove the outbreak.
R1 is not considered by the CDC to be a variant of concern or importance, which means that it is not considered a major threat.
However, 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 contagious and less affected by coronavirus antibodies caused by previous infection or vaccinations.
According to the CDC, about 1.1 percent of all American infections are caused by R1, which is slightly more than that caused by the South African variant, B3151, and slightly less than that caused by the P1 variant from Brazil. .
The R1 variant vaccinated elderly people in the plant at a worrying rate.
More than a quarter of the residents who were fully vaccinated were infected, as well as more than seven percent of staff members.
And according to the CDC study, four people may have been re-infected and developed symptoms with their second attacks of the virus.
The risks of developing the infection were still three times lower for people who were vaccinated compared to those who were not vaccinated.
And vaccinations prevented 87 percent of staff from developing Covid symptoms or being hospitalized for the infection, and 94 percent of hospitalizations among residents were prevented.
By comparison, four out of six residents of the nursing home who had not been vaccinated and coronavirus had to be hospitalized.
However, one vaccinated resident died of COVID-19, as well as two who were not vaccinated.
Overall, the vaccines were about 66 percent effective in protecting residents, who were elderly people with typically weaker immune responses, and 76 percent of staff from infection.
The CDC authors note that the low vaccination rate among staff members probably allowed the dangerous variant – which had never been identified in Kentucky before – to come and spread through the facility.