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A vaccine from Pfizer COVID-19 is less effective at preventing Delta variant infection than previous strains of coronavirus, the latest setback for countries around the world struggling to contain the hyperinfectious form of the virus that causes outbreaks in children and adolescents. A complete vaccine from Pfizer Biontech is 64% effective in preventing Covid-19, according to a previous study, the ministry said Monday, below the previous estimate of 90%.
The study found that a full vaccination triggered the expected immune response to protect people from infection with the new variant. The vaccine initially appeared to be 93% effective at preventing serious illness and hospitalization, but the data showed that the number was lower than previous studies had suggested for other variants.
Clinical trials have shown that the modern RNA-based vaccine from Moderna, Pfizer and Biontech effectively protects people from the disease caused by SARS-CoV-2. A complete vaccination reduces the risk of coronavirus infection by 90%, according to a study of US nurses, firefighters and other frontline fighters who received the vaccine. Israel is one of the world’s most vaccinated countries. More than 60% of the population is vaccinated and two thirds have received at least one dose.
Ran Balicer of Clalit Health Service in Tel Aviv, Israel, and his colleagues found that a Pfizer vaccine with two vaccinations was 94% effective against COVID-19 and 92% effective against serious diseases seven days or more after a second vaccination. Sinovac’s inactivated viral vaccine Coronavac has shown 50% efficacy in preventing symptomatic diseases and 100% protection against serious diseases, according to data from a clinical trial conducted in Brazil. Another study, which was not peer-reviewed, confirmed that a dose of the Coronavac vaccine showed 50% efficacy against symptomatic infections and 35% efficacy during infection associated with circulating P1 variants.
The study covered a period during which a new variant called B117 was circulating in Israel, suggesting that the vaccine could effectively prevent COVID-19 causing variants. Another study from Israel, which was not peer-reviewed, showed that vaccinated people who received two doses of the variant B1351, first identified in South Africa, had fewer infections than those who received the first or second dose and were infected with B117. These results confirm that the two-dose vaccine protects against both B117 and B13 51, but that the latter variant poses a higher risk of its spread, which could be curbed by mass vaccination in conjunction with non-pharmaceutical interventions.
In a preprint of an accepted manuscript, French researchers examined the neutralization effectiveness of SERA in patients vaccinated with the Pfizer and AstraZeneca vaccines and found that one dose of the vaccine inhibited the delta variant while two doses produced a neutralizing reaction in 95% of people with less than half delta. The study used samples from infected and vaccinated patients to find that the neutralization activity of delta variants was lower in the majority of samples from infected patients, while samples from vaccinated patients had no detectable neutralization activity above detection threshold. A press release from the Israeli health ministry states that the vaccine Pfizer is 64% effective in preventing infections and 94% effective in preventing serious diseases.
This week Israel said that the Delta variant blunts the effectiveness of Biontech (BNTX) and Pfizer (PFE-063) COVID-19 vaccines, but the way vaccines work will always fluctuate in the real world and a single data point does not tell the whole story. On Monday, the Dean of the Brown School of Public Health, Dr. Ashish Jha, pointed out in a Twitter thread that the Israeli findings were not consistent with other data on the effectiveness of vaccines against delta variants. Johnson & Johnson (JNJ) unveiled a new study last Thursday which showed that its vaccine neutralizes the antibody activity against delta.
Israel began to vaccine its population and the rest of the world with Pfizer in January as part of an agreement signed with Pfizer in January to collect and share real-world evidence before the vaccines were introduced. On Monday, the Israeli Health Ministry announced that Pfizer’s biontech vaccine was 64 percent effective against coronavirus infections, compared to 95 percent in May when the delta began a rise to near total dominance in Israel. The Israeli Health Ministry tweeted Monday, citing the spread of the delta variant, that the shot was considered 64 percent effective in preventing symptomatic and asymptomatic diseases and 93 percent effective in preventing hospitalizations and deaths.
Studies agree that most COVID-19 vaccines are effective in keeping people out of hospital and protecting them from the delta variant. The Israeli health ministry estimated that the Biontech vaccine of Pfizer was 93 percent effective at preventing serious illness and hospitalization. Pfizer said it and its partner Biontech SE were confident in the protection and safety of the 2-dose vaccine, which prevents serious illness and hospitalization.
The coronavirus vaccine by Pfizer-Biontech has dropped to 64 percent in preventing infections in Israel as the delta variant continues to spread, the country’s health ministry said Monday. According to a new report by the Israeli Ministry of Health, the two-dose vaccine is only 39% effective against the prevalent delta strain, but still provides solid protection against serious illnesses and hospitalizations. According to Israeli data released two weeks ago in March, the vaccine is 99 percent effective in preventing symptomatic COVID-19 and 91.2 percent effective in preventing infection.
In a statement Tuesday, the Israel Health Ministry released information about COVID-19-associated diseases and offered an extended explanation of the protective effect of the vaccines. Despite the apparent decline in the ability of vaccines to prevent infections from the fast-spreading delta variant, the statement stressed its continued usefulness in preventing severe cases. A team of Hebrew University said in a separate statement it was too early to say how much the delta strain had affected the effectiveness of the vaccines.
The worrying delta variant, which is spreading throughout the country, remains a cause for concern, particularly in areas with low vaccination rates. The rapid adoption of infectious diseases in Delta is responsible for spikes in states such as Arkansas, which saw the highest increase of one day in COVID-19 cases since mid-February this week, and Louisiana. There is no good data on whether the vaccine stays even against the delta variant but several commonly used vaccines, including those from Pfizer and Biontech, are in two doses more effective against the variant, said the research.
