Early clinical trial data shows that the Pfizer-BioNTech vaccine intended to be used in children aged six months to five years old is not effective against the Omicron variant.
The Wall Street Journal reports that the smaller, two-dose, regimen was showing effectiveness against the Delta variant when trials first began, but began to falter when Omicron arrived.
Children in the control group of the trial also were very unlikely to catch Covid at all, making it harder for researchers to determine the effectiveness of the shots.
This data was the reason Pfizer decided to add a third shot to the regimen in December, and why its application to receive authorization for the shot was delayed last week, pending additional data.
The Wall Street Journal reports that data from Pfizer’s clinical trials of its COVID-19 vaccine in children aged six months old to five years old did not show effectiveness against the Omicron variant. It is another setback for the company that had to delay the shot’s application for authorization last week (file photo)
The Food and Drug Administration (FDA), which urged Pfizer to submit its application, has not rescheduled its advisory committee meeting to discuss the fate of Pfizer’s additional shot.
The Journal reports that the agency instead wants additional time to gather more infection data and get a stronger look at how effective both the two and three dose regimens.
Immune response data, like antibody levels generate by the shot will be considered in the FDA’s decisions as well.
Pfizer’s shot for young children has already had an extremely rocky rollout, even before it has become available.
Unlike the jab for children aged five and older – which is a two-dose primary series and then a booster afterwards – the initial regimen is three shots for those aged six months to five years old.
The shots are much smaller as well, with each dose only being three micrograms, compared to ten micrograms for the children five to eleven and 30 microgram shots for those 12 and older.
Smaller shots did not generate much of an immune response in three and four year old children, leading to Pfizer adding the additional jab.
Trials for the third shot were not yet completed yet when the FDA requested the application from Pfizer, though, so it only included the first two jabs – with a third to come later.
The testing phase included 4,500 children aged six months old to five, nearly a tenth the size of the 43,000 participant trial used for the company’s bid to have the shot initially authorized for adults in late-2020.
The significantly smaller sample pool likely contributed to the much lower number of infections to work the data with.
Pfizer’s application is currently on hold and remains in limbo until more data comes in. If approved, it would put the U.S. in a class of its own in its vaccine rollout.
Authorization would make the U.S. the country with the youngest minimum vaccination age.
Only two other nations, Venezuela and Cuba, jab children as young as two, and four others – Bahrain, China, Chile and the United Arab Emirates – jab kids as young as three.
None of the countries use the Pfizer vaccine on children, with all opting for either China’s Sinopharm shot or the Cuban Soberena vaccine
If the shot is approved, the U.S. will be the first country to vaccinate children as young as six months old. Some experts disagree that these shots are needed. Pictured: A young girl in New Orleans, Louisiana, receives a shot of a COVID-19 vaccine
Not all experts agree the shot is necessary.
Dr Cody Meissner, the chief of pediatrics at Tufts Children’s Hospital in Boston and a member of the VRBPAC, the FDA committee that will review Pfizer’s application, doubted whether the vaccine is needed for group which already suffers such low risk of hospitalization or death from Covid.
‘I think we’re rethinking the way we looked at this question, because even though people are appropriately vaccinated they are still able to become infected and transmit the virus to susceptible people around them,’ Meissner told DailyMail.com on February 1.
‘So this is a little bit different than many other infectious diseases such as measles, or mumps, or rubella. If you’re protected from infection with the vaccine, then you’re not going to transmit it to other people.’
‘But that’s not the same setting with [this virus].’
He noted that deaths among young children from Covid have remained very low.
According to data from the Centers for Disease Control and Prevention, young children make up less than 0.1 percent of Covid deaths in America.