Are vaccinated people getting COVID-19?
Dr. Aw - Well, as we know, no vaccines are a hundred percent protective and as we've had different variants evolve, that's also affected the way that people respond to the vaccines. So most of our real-world evidence has been from the countries that have been ahead of us in terms of fully vaccinating their population. So places like Israel, United Kingdom, where they've been ahead of us, they've started to notice some breakthrough cases of patients who are presenting with COVID-19.
Now some of the interests around breakthrough infections with vaccines came from a study with about 500 people in Provincetown, Massachusetts, which is sort of a beach resort town. They found that there was an outbreak of COVID-19 and actually over 70% of patients who had COVID-19 were vaccinated. They did find, however, though, they didn't get severely ill, they weren't hospitalized. However, they did find that even though you're vaccinated, you’re still able to carry the virus with the vaccine.
Since then, they've had larger studies from the CDC and the Kaiser, a medical institution that found overall the breakthrough of vaccine infections is about one to two percent. Some of those studies are also corroborated by the Israeli data. So, one to two, one to three percent of real time evidence of breakthrough infections, most of those infections are very mild, in terms of those cases that were immunized that had breakthrough vaccinations.
Again, this is sort of July 2021 data, about less than 1% of them ended up in hospital. So, the risk of getting severely ill for those that are vaccinated is quite low, but one to three percent real-time evidence and the percentage of those folks that actually got hospitalized, like got really sick was even lower.
Now, I think what we'll start to see is more data coming out with the Delta variant in the months to come in terms of what those breakthrough variant infections will be. And the other thing that they've noticed with some of these breakthrough infections is that there's a difference between infection and getting sick and all the vaccines are still very effective in terms of preventing severe disease and hospitalizations, but they might not prevent transmission.
So, this is the reason why we're seeing all these cases. So, you can see, even though you're vaccinated, you still might be able to carry the virus. However, they have found that the degree and the length of transmission is quite low in terms of those who are vaccinated versus unvaccinated. So that's why we still have to be very careful in terms of wearing masks and watching the local community prevalence of disease.
How contagious is the delta variant? I thought you needed to be around someone for about 15 minutes to be infected. Is that still true?
Dr. Aw - Well, we know the Delta variant is very contagious. So, if you think about some of the earlier variants of COVID-19, they said this reproductive rate, this R0 on average would infect one person who might infect two to three other people that are susceptible to the virus. They think that the Delta variant is more in the magnitude of six to eight people, so a R0 of six to eight. So, we know it's very contagious.
We know that it's no longer just respiratory droplets. It's definitely in the aerosol, so it's in the air. And so, another way, sometimes this isn't always the best analogy, but even think about the original alpha variants and these other ones that were contagious, you do a couple of squirts of perfume or a couple of puffs of smoke. The Delta variant might be six to eight squirts of perfume or six to eight puffs of smoke, so it's much more contagious. This is the issue. And as I mentioned previously, even those that are vaccinated can still harbor the virus and still transmit to others, although they are less infective than those that are unvaccinated.
This is why we have to be very careful about wearing masks and the usual hygiene precautions. It's all about ventilation. So, the outdoors, the risks are much lower, but of course, as we're entering the fall, everyone's worried about the indoor air ventilation and air exchanges.
So, this rule about 15 minutes being around someone, I think it doesn't really hold as much as it used to with some of the previous variants. I think its sort of common sense. That is, if you can't prevent yourself from being in close contact with someone, then it's really important to wear a mask. And, if you're in a situation where you don't think that the ventilation is that great, I would very, very much limit and try to maximize the physical distancing from those people. And obviously, the risk is much more lower if you know that the people that you're with, either within your social circles or with your close friends or with your coworkers, if they're fully vaccinated and have a negative rapid antigen test or a negative PCR test, your risk is much more lower.
However, in the general public, if you don't know who these folks are, always be on the side of caution, because we are still in a pandemic, we're entering the fall season. The Delta variant is still an issue, it's highly contagious. So, a lot of this will also be determined by your community prevalence. If the cases are really high where you live, then of course, you've gotta be more careful in terms of the amount of time you spend in close contact with someone that you don't know about their immune status or vaccination status.
However, if there are cases where your community prevalence is quite low and there's a high fully vaccination rate, then it's probably not so bad, right? So, it kind of depends on the situation.
How long are vaccines effective? Will we need to get a booster? If so, when?
Dr. Aw - So, some of the real-world evidence that we're starting to see from countries that we're ahead of, other countries like Israel and United Kingdom, we're starting to see these breakthrough cases of people getting infection even though they're fully vaccinated.
Some studies have shown that the elderly, folks that are older, that were in the first round of people that got the vaccines also had mounted a decreased immune response to the vaccine, even though it was initially very protective, they noticed that at about six months, there's a waning immunity in the elderly.
They also did some big studies in immunocompromised patients, patients who had organ transplants who are on medications, actually studies that were done out of the University Health Network in Toronto, which got a lot of people thinking of changing the recommendations in terms of getting that booster dose of an MRNA vaccine, even after you've had two doses of your preliminary vaccine, and they found that there was a huge boost in the antibody titers for those patients that received a third dose.
So, we've also seen some breakthrough cases in the healthcare workers. So these essential workers in the frontline that have ongoing exposure to patients with COVID, depending on globally where you are and where the community prevalence of the infection is, some of those folks are also starting to get some breakthrough infections.
So having stated all that, different countries around the world are starting to recommend booster doses, but the high priorities remain with the people that are immunocompromised, people who have a weakened immune system because they didn't mount a higher immune response to the vaccine in the first place, and some data has shown that they will receive a booster in terms of immunity with the third dose.
Also with the elderly, I think because they're at such high risk of mortality, bad complications, hospitalizations, I think you're gonna see booster doses also being recommended for the elderly, and then maybe the next group of folks might be the essential workers, the frontline workers, for which at least six to eight months have elapsed from their first vaccine, the second shot of vaccine I should say.
However, I think you're gonna see more evidence, right now the medical community is debating really whether everyone should get a booster vaccine dose at this point. I think it's complicated in terms of looking at, you know, the different markers of immunity. That's what they're trying to figure out right now
Not to get too complicated, but there's antibodies, there's B cells and then there's T cells, which are kind of your local immune response at the cellular level. So I think, and there's nasal mucosal immunity versus systemic immunity.
So all these things are kind of variables that the medical community will have to figure out
in terms of markers of immunity and who will get the vaccine booster dose.
It is also a global inequity situation, as we all know, about 10 countries dominate about 70% of the vaccine distribution globally, and the developing world only really has about 2% of their population vaccinated. So I think there's an inequity situation too, to make sure that we distribute the vaccine globally to those people at risk, so we can get ahead of this pandemic and then protect the ones that might cripple our healthcare system, or have the worst outcomes from the vaccine.
I'm sure a lot of us parents are wondering with kids under 12 still unvaccinated what should we expect for return to school?
Well, the good news is that the vaccines have been approved for the 12 to 17-year olds. They're starting to get vaccinated. They're starting to catch up. As we know, the school year is upon us. We know about the benefits on the mental health and developmental benefits of children getting back into a social structure in terms of school, being around their peers and getting educated.
Also, there's some normalcy for the parents with young children, so that there's not this hybrid world, which can create a lot of confusion and stress at home, and also even in the workplace in terms of juggling both hats.
Having said that there are a lot of studies going on right now. Now we know, gosh, over 5 billion doses of this vaccine have been given globally. We know it's safe, but what's not often spoken about is that there's been no real deaths. And, you know, in terms of all these vaccines that have been given out and the side effects are really, really low.
Fortunately for the children real time, real-world evidence is being that fortunately that, you know, the virus and the infection is quite mild in children. And really, we're waiting for safety data and trying to get our handle on the right dose for children. So I think, you know, that data might be coming out November, maybe December in terms of recommendations of what the right dose and booster schedule might be for children.
But for now, I think it's important for kids to get back to school. Outbreaks within schools tend to be associated with how much of the virus is in the community. So, if the community prevalence of cases is quite high, and the vaccination rates are quite low, we would tend to see that within the kids. Kids might not get sick, but the secondary transmission of cases is quite high in households. So it's all kind of connected.
So if you go backwards, if the community prevalence is quite low, if all the teachers, if all the adults, if all the parents are fully vaccinated to shots, that's great.
If the kids are compliant with wearing masks, you know, as best that they can, you know, young children aren't always going to put these masks on, but best that they can, and if there's even more progressive or forward-leaning testing protocols within the different institutions that might be able to control the super spreading events.
But they found that these outbreaks are really linked to what's happening in the community. So fortunately for children, they don't tend to get really sick with this disease. There are tests now available, Rapid Antigen Tests, things you can even buy at the pharmacy. People are getting vaccinated, vaccines are coming.
So I think you know, more and more data will be coming out in the fall, so that we'll have a better handle in terms of the full recommendations for our children.