FDA to Approve Omicron Booster
By Jared Dashevsky
The FDA is expected to approve Pfizer and Moderna’s updated Covid-19 booster vaccine this week, which covers the dominant BA.5 Omicron subvariant. mRNA technology is remarkable. The BA.5 subvariant started picking up steam back in June, and here we are nearly three months later with a vaccine ready to go.
Pfizer and Moderna’s updated booster vaccines are bivalent, targeting the dominant BA.5 omicron subvariant and the original Covid-19 strain. This is the first updated Covid-19 vaccine.
Immunity against Covid-19 has been waning likely because of immune escape and evolved viral spike proteins, allowing the virus to bind and fuse to cells more effectively. There are around 30 mutations in Omicron’s spike protein, 15 of which are the critical targets of neutralizing antibodies produced from vaccines and therapeutic antibodies. So, these mutations challenge our immune system’s ability to detect and neutralize the variant, allowing the variant to escape from our immune system and infect cells. The new vaccine, theoretically, is equipped to better our body’s ability to detect BA.5‘s spike protein and neutralize the virus.
Of note, the approval of this updated vaccine will be similar to how the annual flu vaccine is continuously updated and approved, which means clinical data is unnecessary. This, therefore, sets a precedent for the FDA to approve the BA.5 vaccine based on mice data.
The vaccine, when approved, will be available for those 12 and older for Pfizer’s vaccine and 18 and older for Moderna’s vaccine. The government has already purchased 175 million of these updated vaccines for around $5B. Specifically, this includes 105 million doses from Pfizer for $3.2 billion and 66 million doses from Moderna for $1.74 billion.
My three main concerns, or thoughts, are the following:
- Will it work?
- Who are the winners?
- What’s next?
Will it work?
Covid-19 isn’t the influenza virus, and it may be challenging to extrapolate mice data from the updated vaccines to humans. As such, there is a possibility that the updated vaccine won’t be as effective in humans as it is in mice, which demonstrated a two-fold increase in BA.5 neutralizing antibody. But, there’s a possibility it is as effective—which would be great. However, since there are no clinical trials yet for the updated vaccine, it’s impossible to know whether it will be as effective or better than receiving another booster of the regular vaccine. TBD.
Who are the winners?
Pfizer and Moderna are the winners, given the U.S. government has already purchased millions of their doses for billions of dollars. Both companies had a profitable year in 2021 (I covered Pfizer here). I expect the companies to contract more with other governments for this updated vaccine. I just hope they do so in an equitable manner.
We humans are also the winners, given we will now have a more updated tool in our immunity repertoire. This may be true at an individual level—you and me. But on a population level, it is not. The rate of booster uptake in the U.S. is abysmal compared to peer nations, coming in at 33%. So, any additional vaccine that comes out, will likely only benefit those who have been willing to get the booster shot(s) so far.
Is this the start of an annual coronavirus vaccine? Given how quickly and scalable mRNA technology is, creating a vaccine that targets the most dominant variant is easy compared to traditional methodologies. So, I say the answer is yes.
Additionally, Drs. Eric Topol and Akiko Iwasaki are bullish on intranasal vaccines, which may be more effective in inducing respiratory mucosal immunity. There are several nasal vaccines in the pipeline, expect to hear more about them over the next couple of months.