SAN ANTONIO – Dr. Bryan Alsip, the chief medical officer with University Health System answered some frequently asked questions about COVID-19 boosters, how our immune system works and the latest mask guidance.
You can watch the full Q&A in the video player above.
What are some reasons people may not be getting their COVID-19 booster?
Alsip: Well, I think there may be a lot of reasons people aren’t getting their boosters. Certainly, we’ve got a lot of individuals who are fully vaccinated, which means they’ve had their first two doses of one of the many vaccines, or a single dose of the Janssen vaccine. And they probably feel there’s some amount of protection with that. There’s certainly no lack of opportunities to get a booster. But we’ve seen that lower percentage of uptake among boosters, even for those who were very eager to get the first primary series. Even among health care workers, it’s not as high as we would like it to be. So there’s, in some cases, perhaps some misunderstanding of the value of what boosters are and how they can help. And so people might not feel as needing an extra shot because they’ve actually already had a full series of the COVID vaccine.
If my antibody count has dropped, does that mean my immunity has waned?
Alsip: Possibly. But, you know, immunity as measured by our antibody level is really only one aspect of our immune system. It’s actually a very complex system and there are a lot of parts to it. And so antibodies are certainly one of those because they are made by our white blood cells and they attach to viruses or bacteria that invade our bodies and enables them to be either destroyed or are prevented from replicating. But we also have other parts of our immune system that are working, and we know work, and that’s harder to measure. And so your antibody levels alone are only one measurement of how well your immune system is working.
How does a booster increase protection? Does it just give us more antibodies?
Alsip: Well, a booster does a couple of things. It helps remind our immune system of the pathogen we’re trying to protect against — and that does often stimulate more antibodies — but it also, I think, helps our immune system work better. We found that boosters oftentimes will help our immune system recognize pathogens more quickly. So not only do you have more antibodies in terms of overall defense to protect you against that pathogen, but it probably recognizes it more quickly. And that’s another way to sort of help boost our immunity and our protection.
Besides antibodies, what are some other parts of our immune system?
Alsip: Well, you know, our immune system is complex and there are several parts, but one of the big parts of our immune system is what our white blood cells do. And so we have red blood cells, which people are familiar with and white blood cells and the white blood cells are the ones that fight infection. And within that group, we also have what are called B cells and T cells. B cells primarily are responsible for creating those antibodies that we hear a lot about, which offer protection. What they do is they attach to bacteria or a virus, and that either presents it to a cell that will destroy it in our immune system, or it just could sort of render it less likely to infect our own cells. The T cells come in a couple of categories — there are helper T cells that actually work to make those B cells better in terms of how they work and other T cells that are killer T cells, which means they actually go after our own cells that are infected with those viruses or bacteria. So they can’t spread or they can’t cause illness or severe disease.
For how long after a vaccination are we protected by these B cells or T cells?
Alsip: So we think for the most part, vaccinations with the current COVID-19 vaccines last at least six months and maybe longer. We’ve seen in some individuals with just a primary series that immunity can last longer, but it’s measured in different ways. It’s measured by your antibody levels, but also by our ability to simply prevent infection. So simply because your antibody levels go down doesn’t mean you can’t be protected against infection. And conversely, if your antibody levels are high, that’s not necessarily a guarantee against infection. But the most important thing about the vaccinations is that we know they’re very good at preventing severe illness, hospitalization and death. And so they certainly last six months, they could last longer. And that’s another reason why we feel the boosters are important because it really boosts that immunity in a couple of ways. And most of the recommendations now are around, at least for the mRNA vaccines, about five months or so after you’ve received your second dose at the end of your primary series, you should get that booster. That way, you don’t sort of get to a point where your antibody levels are dropping before you get that immune response.
How much will I be protected from future COVID-19 variants — like BA.2 — by being up to date and boosted?
Alsip: Well, the good news is what we’re seeing is vaccinations, particularly with boosters, not only has a longer lasting effect, but seems to work fairly well against even new variants. Certainly the most prolific variant we’ve seen recently is the Omicron variant, and early studies are showing that individuals who are fully vaccinated with a booster or up to date with their vaccinations have a very strong response in protecting them against severe disease and hospitalization, which is really the most important part. There are certainly breakthrough infections, but we know that that booster is really a very important part of extending the duration of that immunity and also making sure that it’s more effective.
Are we seeing BA.2 in Bexar County?
Alsip: The latest data I have looked at has not necessarily indicated BA.2 in the sense that the sequencing done at UT Health has not identified it, but there are indicators that it could be in the community. There have been over a dozen cases, I think identified, at least in the state of Texas. There are some indicators on the Community Labs testing that suggests that it could be consistent with BA.2. But until we see it, we don’t confirm it. But that doesn’t necessarily mean it’s not here and circulating in some capacity.
I’ve already had COVID-19. How does being up to date and boosted compare to natural immunity from a COVID-19 infection?
Alsip: We know that natural immunity does confer some protection, and that’s important because it also can supplement other protection or immunity you get from vaccination. In fact, some of the studies we’ve seen show that if you’re vaccinated and had a previous infection, you really are someone who has extra protection. And so that’s a good thing. What we don’t know is how to measure the natural immunity that comes from being naturally infected as well. We also know that it varies significantly person to person. If you’ve had maybe a severe infection, your level of immunity might be very different from someone who had a very minor infection. So it’s harder to rely on natural infection as your sole source of protection, and we certainly don’t know how long it lasts. So that’s why we recommend even if you have had COVID to get immunized and be up to date with those vaccines.
What happens if you are not boosted and catch COVID-19 in a breakthrough infection, compared to if you are up to date?
Alsip: Well, if you’re up to date, that means you’ve had the booster that you’re eligible for, which means you’ve had that additional dose, which means you are better protected. Having at least two doses or being fully vaccinated is better than not. But we have seen and continue to see as data come in that being up to date with a booster is better. It’s longer lasting immunity. It’s better protection in terms of your response to infection, so you’re less likely to get severe illness or be hospitalized. It just adds an additional layer of protection that we know is helpful, particularly amongst those who might be at higher risk.
Why does the CDC now recommend longer intervals between shots in the COVID-19 vaccine series?
Alsip: Well, the CDC recently updated some of their guidance regarding the intervals between doses of a two-dose series of an mRNA vaccine for COVID and for the most part, most people could probably extend the duration between the first and your second dose. Rather than from three weeks with Pfizer or four weeks Moderna up to about eight weeks before you get that second dose. What the CDC is indicating is that data showing that probably leads to a better response and probably something that might make the vaccine last longer. They do say for certain populations, they might want to consider continuing with the shorter interval. Individuals who have moderate to severe or immunocompromised, or those who are at higher risk because of an age level greater than 65 years of age or other potential risk factors that would prompt you to need to have that second dose earlier. But I think that supports what we know about vaccines that you really shouldn’t get a vaccine earlier than recommended, but you can always get a vaccine later than recommended. And sometimes when you get that later dose, it confers immunity that’s longer lasting.
What do the new CDC masking recommendations mean for our community?
Alsip: Well, if we take it at a community level and San Antonio is assessed at a low-risk category, it may be that for most people, the CDC recommendations align with not requiring masks to be worn in indoor settings. There are caveats to that — if you’re at high risk for COVID disease, if you have severe or moderate immunocompromised or if you’re at a certain age level, say greater than 65 years of age or some other medical condition of concern, they might still recommend wearing a mask in those settings. It’s also important to recognize that currently where we are in the pandemic and they’re still circulating many other respiratory illnesses to include influenza, and so there’s still some benefits to wearing a mask in indoor settings to protect yourself against other pathogens.
Do the new CDC masking recommendations apply to everyone?
Alsip: Well, it applies to everyone in the general population, or the CDC would recommend also that there are individuals potentially at higher risk that should still continue to wear a mask or consider continuing to wear a mask. And that would be individuals who are moderately to severely immunocompromised, individuals greater than 65 years of age, or those with high risk medical conditions that might make them more prone to severe illness if they were to catch COVID. I think it’s also important to recognize that we often look at the guidance from the CDC and for health care workers separate and apart from those guidance for the general population. And we’ve seen that with respect to isolation and quarantine requirements that are different. The mask guidance for health care workers is also different from that with respect to the general population, because where we work and how we interact with patients puts us at a higher risk. And so those guidelines are actually different for that population.