Pfizer says their vaccine protection lasts at least 6 months
Pfizer also announced their vaccine protects against the South Africa variant that's been causing concern
LINCOLN, Neb. (KLKN)-Pfizer/BioNTech’s Phase 3 clinical trial of their COVID-19 vaccine has confirmed that its protection will last at least six months after the second dose, the companies announced on Thursday.
This is the first report of how long protection for a COVID-19 vaccine lasts. The best estimate so far has been that it’s longer than 90 days.
Pfizer’s vaccine is 91% effective against disease with any symptoms for six months, according to the company. They’ve also reported that their vaccine is fully effective against the B.1.351 variant of the virus that’s circulating through South Africa and causing concern.
“The vaccine was 100% effective against severe disease as defined by the U.S. Centers for Disease Control and Prevention (CDC), and 95.3% effective against severe COVID-19 as defined by the U.S. Food and Drug Administration (FDA),” Pfizer and BioNTech said in a joint statement.
“The high vaccine efficacy observed through up to six months following a second dose and against the variant prevalent in South Africa provides further confidence in our vaccine’s overall effectiveness.”
Pfizer has studied its vaccine in over 46,000 volunteers and has reported 927 confirmed cases of COVID-19.
“From the 927 confirmed symptomatic cases of COVID-19 in the trial, 850 cases of COVID-19 were in the placebo group and 77 cases were in the BNT162b2 group, corresponding to vaccine efficacy of 91.3%,” the company said.
“Thirty-two cases of severe disease, as defined by the CDC, were observed in the placebo group versus none in the BNT162b2 vaccinated group, indicating that the vaccine was 100% efficacious in this analysis against severe disease by the CDC definition. Twenty-one cases, as defined by the FDA, were observed in the placebo group versus one case in the BNT162b2 vaccinated group, indicating 95.3% efficacy by the FDA definition.”
The FDA’s definition of severe disease included a raised respiratory rate indicating respiratory distress; raised heart rate, an oxygen saturation level of 93% or lower; respiratory failure severe enough to need additional oxygen or ventilation; a blood pressure drop indicating shock; significant kidney, liver or neurological dysfunction, admission to an intensive care unit or death.
CDC’s definition includes a blood oxygen level of 94% or lower and an x-ray finding of lung infiltrates — an indication of pneumonia — of greater than 50%
When it comes to adverse events following a vaccine injection, the most common ones reported were pain at the injection site, fatigue, and headache.
“In South Africa, where the B.1.351 lineage is prevalent and 800 participants were enrolled, nine cases of COVID-19 were observed, all in the placebo group, indicating vaccine efficacy of 100%,” the company said.
“Vaccine safety has now been evaluated in more than 44,000 participants aged 16 years and older with more than 12,000 vaccinated participants having at least six months of follow-up after their second dose.”