Moderna COVID-19 vaccine over 90% effective 6 months after booster shot, data shows

Moderna says its COVID-19 vaccine is more than 90 per cent effective against the virus at least six months after receiving a second dose.

Referencing preliminary data released Tuesday from its Phase III clinical trial, the pharmaceutical giant said in a press release its vaccine was up to 95 per cent effective against “severe cases of COVID-19.”

Moderna also said its vaccine booster geared towards variants of concern showed an increase in “neutralizing titres” against known strains of the virus. A titre is laboratory test that measures the presence and amount of antibodies in blood.

“The new preclinical data on our variant-specific vaccine candidates give us confidence that we can proactively address emerging variants,” the press release said.

The mRNA vaccine developer said the vaccine’s efficacy kicked in two weeks after the second dose. Data from the Phase III clinical trial evaluated over 900 cases of COVID-19 until April 9, including more than 100 severe cases of the virus.

The news comes after a study published in the New England Journal of Medicine on April 6 found antibodies produced by Moderna’s vaccine maintained a 94 per cent efficacy rate that began 180 days after the second dose.

It also comes after a week-long delay over a previously promised batch of 855,000 Moderna doses. On Monday, Maj.-Gen. Dany Fortin, the military commander leading the federal government’s vaccination distribution effort, blamed the delay on a “backlog with quality assurance.”

Canada has pre-ordered 44 million doses of the vaccine and has already distributed more than 2 million doses across the country.

Health Canada approved the two-dose Moderna vaccine in December of last year. It has been authorized for adults aged 18 years and older.

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Moderna is in the process of testing its vaccine on children aged 17-years-old and younger.

The vaccine developer said its trial for those between the ages of 12 and 17 years was now “fully enrolled” with around 3,000 participants from the United States, while its paediatric trial for children aged between six months and 11 years is “currently enrolling.”

Moderna said it expects to enrol 6,750 healthy children in that age demographic into its two-part, two-dose study from Canada and the U.S. Dose levels will vary based on age.

The pharmaceutical giant said an interim analysis will also be conducted to “determine which dose will be used in Part 2, the placebo-controlled expansion portion of the study.”

Trust in the Moderna vaccine is currently much higher than that of AstraZeneca.

In a poll of 1,523 Canadians conducted by Leger and the Association for Canadian Studies at the end of March, 77 per cent of respondents said they felt they would trust being injected with the Moderna vaccine. Meanwhile, just 53 per cent said they would feel comfortable being jabbed with a dose of AstraZeneca.

Pfizer-BioNTech was found to be the most trusted vaccine so far, standing at 82 per cent.

A European Medicines Agency’s review in March that found a “possible link” between the AstraZeneca vaccine and blood clots, but deemed it safe for use. The agency’s review has prompted many European countries to change their recommendations for the shot.

On Tuesday, Quebec provincial health authorities announced its first report of a rare blood clot in a person who had received the AstraZeneca COVID-19 vaccine.

“The person was taken care of by the health and social services network and received the care appropriate to their condition,” Quebec health officials said in a statement. “She is now recovering at her home and there is no fear for her life.”

— with files from the Canadian Press