The Covid vaccine battleground gets younger

The FDA has finally confirmed the date of a review of Covid vaccine data in the very young, but has Pfizer/Biontech already won the race?

The arms of the very young represent the final frontier for Covid vaccine makers – in rich countries at least – and, with the FDA finally firming up its review of results generated in infants, approvals could soon be on their way in the US.

Impressive data toplined by Pfizer and Biontech yesterday in under fives showed Comirnaty to be highly effective and as safe as when used in older children and adults, so approval seems likely. The stakes are higher for Moderna, which has yet to generate similarly convincing data or win any US authorisations in under 18s, and has seen sales forecasts for its vaccine, Spikevax, head lower.

True, both developers have struggled to prove that their shots work as well in children as in adults, largely because of the Omicron variant, which has eroded the effectiveness of all the available vaccines. Getting the dose right in the very young has also proved tricky, however.

Pfizer and Biontech had to add a third jab to their schedule for children under five to achieve the 80.3% efficacy rate unveiled yesterday. This extra shot, given at least two months after the primary two-dose series, was added to the clinical trial after an interim immunogenicity analysis found that two to five year olds were not getting a sufficient immune boost.

Moderna maintains that its trial in children shows Spikevax, given in a two-series schedule, eliciting a similar immune response to that seen in adults. Vaccine efficacy is “consistent with observational data” from adults in the Omicron wave, the company has said, with the shot 43.7% effective at preventing symptomatic infection in children aged six months to two years, and 37.5% in the two to six year age group.

What the FDA and its advisory committee makes of all this will soon be known, with two dates in June now set for discussions.

VRBPAC advisory committee meetings for Covid vaccines
Product Current approvals Adcoms
Comirnaty (Pfizer/Biontech)  Full approval for 16+; EUAs for two-dose primary series for 5+, 3rd primary shot for 5+ with immunocompromise; and as a first/second booster shot for various 12+ groups June 15: to discuss EUA request for 6mth to 4yrs of age
Spikevax (Moderna) Full approval for 18+; EUAs for 3rd primary shot for 18+ with immunocompromise; and as first/second booster for various 18+ groups June 14: to discuss EUA request for 6 to 17yrs of age
June 15: to discuss EUA request for 6mth to 5yrs of age
Nuvaxovid (Novavax) No US approval (approved in Europe, Canada and other regions) June 7: to discuss EUA request for 18+yrs of age
Note: a further adcom will be held on June 28 to discuss whether the Sars-Cov-2 strain composition of Covid vaccines should be modified, and if so which strain(s) should be selected for autumn 2022. VRBPAC = Vaccines and Related Biological Products Advisory Committee. Source: FDA.

The US contains some vocal supporters of vaccinating the very young, for whom these approvals cannot come soon enough. But while approvals are widely expected the timing of the adcoms, in particular the substantial delay in reviewing the Spikevax data, arguably makes the outcome for Moderna’s vaccine less certain.

The company said it would seek emergency authorisation back in March, and the three-month wait for this hearing has raised eyebrows. Many reasons have been suggested by regulatory experts, from a desire at the FDA to evaluate these packages side by side, to siding with Pfizer and potential worries about the Moderna data package.

All of this remains conjecture for now. But one thing is certain: Comirnaty’s huge lead in the space is unlikely to be threatened by the outcome. It has been available for the over fives in the US since last October, and its existing authorisations exceed those won by Spikevax.

The Covid tail

A bigger question for financial analysts is what long-term demand looks like for all the Covid vaccines. On Pfizer’s recent earnings call executives were repeatedly pressed on what they saw for 2023 and beyond. Given the unpredictable nature of the pandemic, they understandably refused to be drawn.

Evaluate Vantage calculates that consensus for Spikevax and Comirnaty shifted in opposite directions after the developers’ respective first-quarter updates. Around $4bn was added to Comirnaty's consensus, taking it to $19bn for 2023, while $2bn was shaved from Spikevax, leaving $9.3bn.

Many banks have taken longer-term numbers for both products lower, however. By 2026, consensus for Spikevax is currently around $4bn – although some analysts have pencilled in as low as $2.6bn – while Comirnaty is expected to be pulling in more than $6bn by then.

Should regulators decide that new vaccine recipes are needed to address the current or future variants, perhaps Moderna will have a chance to cling on to bigger share of the booster market. Data on an Omicron-containing bivalent booster are due in June from Moderna, and could prove important in determining what happens to the Covid tail.

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