New COVID Boosters

Many people have questions about the new COVID vaccine boosters.  Keep reading for answers to some of the most common ones here.

What’s new in this latest round of COVID vaccine boosters? 

The original COVID vaccines were effective at preventing infection and very successful in preventing complications from the Alpha and Delta strains.  But they are less effective against the Omicron variants which are more transmissible and immune-evading.

On September 1, 2022 the CDC approved new boosters from Pfizer (for ages 12 and up) and Moderna (for ages 18 and up).  These updated boosters add Omicron BA.4 and BA.5 to the original vaccine composition. 

Moderna COVID-19 vaccine, Bivalent is the name for Moderna’s new booster.  Pfizer’s new booster is called Pfizer-BioNTech COVID-19 vaccine, Bivalent.  Bivalent just means there are two strains in the vaccine (alpha and omicron).  I think we should call it COVID vaccine 2.0.

Is it better than the original?

As COVID has mutated into different strains and subvariants, it has gotten better at evading the vaccine.

For the original strain (Alpha) and the later strain (Delta), Pfizer and Moderna initial two-shot series were about 75% effective at preventing infection and 90-95% effective at preventing serious complications.  But the vaccines were less effective against Omicron – only 30-40% protection against infection and 70% protection against hospitalization.  A 3rd booster shot boosted effectiveness against infection to 75% and 88% for severe disease.

Unfortunately, it’s unclear exactly how much protection the new booster shots will provide, but models suggest 80% protection from infection and around 90% for prevention of complications. 

How could they approve the new booster without large clinical trials?

Believe it or not, this is something that has been done for decades with the flu shot.  The flu shot is reformulated every year based on an educated guess of what the circulating strains will be in the coming year.  They might take 1 or 2 strains out and put in different ones. 

Flu shots are made using eggs and take 9 months to produce.  Because large clinical trials require time (a minimum of 3-6 months, often longer), it’s not feasible to run clinical trials each year.  They have decades of data showing the vaccine is safe and effective (some years more than others), so they approve the latest formulation based on that history.  This has been a very effective strategy allowing the flu shot to adapt each year just in time for the next flu season.

They have adopted a similar process for the new COVID vaccine booster.  They have extensive safety and effectiveness data for the original COVID vaccines (over 600 million doses given in US).  Additionally, they have safety and immunogenicity data from a clinical study of a bivalent COVID-19 vaccine that contained mRNA from the Alpha strain and mRNA from the original Omicron strain (not BA.4 or BA.5 subvariants).

Should I get one?

Yes.  I plan to get mine and will give it to my 87-year-old mother.  I’ve encouraged my children (in their 20’s) to get it as well.

When should I get it?

Although you can get it as early as 2 months after your previous booster, I recommend waiting 4 months after your last booster.  That’s the point where the vaccine efficacy seems to drop. 

Another consideration is the current amount of COVID infections.  Currently cases are relatively low.  We are anticipating a surge in December/January, like what we’ve had for the past two years.  So, you might want to get the booster in October or November to have good immunity in December and January.

Does the new booster have side effects?

They are expected to be similar to the original vaccine – soreness in arm, body aches, fever, etc.

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