SAN ANTONIO – Moderna and Pfizer rolled out updated boosters this month with a new formula that better fights against the BA.4 and BA.5 omicron relatives responsible for most of today’s COVID-19 cases.
The updated shots are only for use as a booster, not for someone’s first-ever vaccinations. The Food and Drug Administration cleared Pfizer’s bivalent option for people 12 and older while Moderna’s is for adults only.
What makes these new boosters different from the old ones? Who should get them and when?
Dr. Bryan Alsip, the Chief Medical Officer with University Health, answered some commonly asked questions. You can watch a video in the video player at the top of this article and read his answers below:
What is the difference between the old mRNA COVID-19 boosters and the new ones?
Dr. Alsip: So the new shots are the first real updates that we’ve had to the COVID-19 vaccines since they were originally introduced in the late period of 2020. So all of the vaccines that we’ve gotten up to this point, whether they were in the primary series or booster doses, were the same type of vaccine. And that was built off the original strain of the SARS-CoV-2 virus. The key difference between that vaccine and the most recent vaccines is that the new ones are what they call a bivalent vaccine, which means they have components of both the original strain of SARS-CoV-2 virus, as well as the Omicron subvariants that are known as BA.4 and BA.5. And since those are the predominant strains that are circulating worldwide, particularly BA.5, it’s felt that this newer vaccine will be one that offers better protection and longer-lasting immunity. And it’s called a bivalent vaccine because it has those two components. One is the original strain and one is the new subvariants of Omicron.
I recently got the monovalent COVID-19 booster. Am I eligible for the new bivalent booster?
Dr. Alsip: Yes, you’re eligible for the bivalent booster. In fact, it is the only vaccine you should get as a booster dose. The monovalent vaccine is still available, but it really is only for individuals who have never had the COVID vaccine. So it would be what’s called the primary series that they should get as their first two doses.
How long should I wait after recovering from COVID-19 to get the new booster?
Dr. Alsip: The FDA has authorized and the CDC has recommended that you wait at least two months after your most recent booster dose before you receive the bivalent vaccine.
I just got over COVID-19. If it was an Omicron subvariant, don’t I already have protection against future Omicron infection?
Dr. Alsip: Yes, you actually do have some protection. In fact, we know from previous studies with other variants of COVID, that you have some natural immunity from a previous infection. And that’s one of the reasons why they recommend waiting for an interval of time before you receive a booster dose. In this case, the CDC is recommending you wait at least three months at minimum between your recent COVID infection and receiving the bivalent vaccine.
How long should I wait after recovering from COVID-19 to get the new booster?
Dr. Alsip: So if you have recently had an infection the CDC recommends you wait at least three months before you receive the Bivalent vaccine booster. However, you could wait longer. As with most vaccines, you’d never want to take a vaccine shorter than that interval or sooner than is recommended. But you can always take it later than is recommended. And in some cases, there may be some benefits to actually getting that booster at a later time.
Why is it better to stretch out the waiting period between vaccination or recovery and getting the new bivalent booster?
Dr. Alsip: Well, with many vaccines to include COVID, immunologic studies have shown if you extend that interval between doses, you can actually improve that immune response as well as maybe the duration of protection. It certainly felt that in some cases extending that interval — in this case from, say, 2 to 3 months to something like 4 to 6 months — may give you a longer-lasting protection because it increases the number of neutralizing antibodies, which are the antibodies that actually target the pathogen, in this case, the SARS-CoV-2 virus. And it also increases the activity of B-cells and T-cells, which are part of our immune system.
What are B cells and T cells and how are they different from antibodies?
Dr. Alsip: So B cells and T cells are parts of our immune system. They are actually white blood cells. B cells actually produce the antibodies that people know about and antibodies really are the ones that target those pathogens, whether it’s bacteria or viruses or even toxins, in some cases. T cells actually attack other cells that are infected with those pathogens. And so really, they’re both a part of our comprehensive immune system that helps protect us from disease.
Why is hyperactive immunity?
Dr. Alsip: So hyperactive immunity is just a general term for an overactive immune state, and that can happen with certain diseases, but it also can happen with a normal response to either an infection or a normal response to a vaccination. And what it implies is there’s a sort of a plateau or a high level of effectiveness of our immune system. So if you are in a hyper-immune state, there’s probably limited benefit to getting another vaccine dose. It really doesn’t add to the ability to respond more quickly. It doesn’t provide a longer response. However, if you come out of that hyper-immune state, which often happens with the longer interval between doses, that next booster dose really has a greater effect to enhance your immune system response, therefore give greater protection, and could last longer, as well, in your system to protect you against disease.