Infectious Disease Physician, Brigham & Women’s Hospital
A new flu vaccine is needed every year because the influenza virus is constantly evolving, changing its outer proteins. International flu surveillance centers are used to anticipate what strains will be most prominent in order to create a targeted vaccine for that season. Transcript: "So, why is there a new flu vaccine every year? Well, the influenza virus, like most viruses, contains a set of genes that are wrapped in a coat of protein. The way vaccines typically work is that for the flu vaccine, it stimulates the production of antibodies that then attach to the outer structures on this protein coat of the virus. And in doing so, it then disables the virus or prevents it from being able to actually enter into our cells and infect us. And so, given that, the way viruses go and the way the flu virus is, is that it is constantly evolving and when it evolves, it changes those outer proteins. And so, therefore, we need a new vaccine that is able to stimulate antibodies against the current proteins that's in the outer coat of the virus. As a result, we know that we have to really do a close surveillance, of which we have internationally, these influenza viral surveillance centers, that are really trying to see if they can anticipate what are the likely strains of the flu virus. That we could they can then use to target the future years vaccine towards. And so, what we do in north America is that we look to see what is happening in the other parts of the world, in Australia, et cetera, to then say can we anticipate that. And so, some years and some seasons we get it very close and accurate, and other seasons we don't. But this is why every year we get a new flu vaccine."
The incubation period for covid-19 is usually 2 to 4 days, with the current variance, it can be up to 7 days. Transcript: "Hello, and Willie here. And I'm going to Texas, diseases, specialist at Brigham Women's Hospital in Boston and the question I'm going to answer for you. Today is, what is the incubation period for covid-19? Well, initially in 2020, and 2021, with the earlier, SARS Covey, to variance, and that refers to the different formulations of the virus that we have seen that have mutated over time. Since we first had Stars, Kobe to the outbreak that we saw in the u.s. in early 2012. Monty we've seen different periods of incubation time. So initially, we thought of that, it was up to anywhere up to 10 to 14 days where the majority of individuals that have been exposed to covid that they would then have an onset of symptoms or test positive around five to seven days. What we're seeing now in the past nine months or so with the Omicron variant is it a much shorter incubation period of time and so for most individuals once you're exposed to covid to when you will manifest symptoms of covid-19 and or test positive for covid-19 is usually between 2 and 4 days from when you were exposed to the virus. This does not mean that if you don't test positive by day for that you couldn't then go on to still test positive after day for but I'd say the vast majority test positive by day five now and very rarely is it a case where an individual who has been exposed to covid? Five days ago, does not test positive until day 7 or date and so usually, when I think about the incubation period of time of what I'm most concerned about it. And counsel, our patients, it's two to four days. Now, the current variance, however, it can be up to 7 days and we should think about that when we're thinking of, in terms of, if you are at risk for exposing other individuals, if you've had a very high risk, exposure yourself,"
We recommend that individuals who have had covid-19 infection wait at least one month to three months after infection before having their booster dose, so that they can mount a better immune response. Transcript: "Hello. My name is an Woolly and I'm an infectious disease specialist. And I'm going to answer the following question about whether individuals who have had covid-19 infection should be vaccinated and or boosted. And if so what is the ideal timing after covid-19 infection to receive the vaccine doses? Well, we know this has been a well, discussed well-researched area within covid-19, backsons 2021 when vaccination became widely available and so we know that most individuals will mount a very Response to having had natural infection, having had covid infection itself, and so therefore, there's no rush to get to your next vaccine dose after having had covid. However, we do have been plenty of studies that have shown that just because you've had covid-19 the humoral response or the immune response that your body mounts may not last as long as those individuals who have been vaccinated. So just having had covid-19 is not a reason to not get vaccinated and not to continue. In you, on the schedule of getting your booster doses, we still very much recommend that. Therefore, what we recommend is that you wait at minimum, the amount of time it takes for you to become asymptomatic and to complete your isolation period. So, most recommend, at least a month after having covid-19 infection, to wait for vaccines. However, there are mounting data to show that perhaps, if you were to wait a little bit longer. And wait, at least three months after you've had covid-19, you may actually have an augmented. Meaning a better immune response when you do go and get that vaccine dose that booster dose now and so I would recommend that you definitely get your vaccine or right now the bivalent booster dose if you're due for it. And if you've had covid-19 that you get it anywhere from one month to three months, after having covid-19 infection, so that you continue to have a good immune response to protect you from severity of illness. If you were to get exposed covid-19 again,"
A persistently positive PCR test for weeks after COVID-19 infection does not necessarily mean an individual still has active infection, as the virus may be present in the form of shedding rather than replicating. It is best to use a rapid antigen test to determine if an individual has enough virus to cause symptoms and transmit the virus to others. Transcript: "Hello. This is an Willie, I'm an infectious disease specialist and this is a great question that we received. What is the significance of a persistently positive PCR test for weeks after covid-19 infection? Well, let's first take a step back and talk about what does it mean to have a positive PCR covid-19 test? So what that means is that we have detected SARS Covey to the virus that causes covid-19 we've detected RNA. The Tsar is Covey to RNA Detected by PCR in order to say, that's an individual has covid-19. So we get that test obviously to see if an individual is acutely infected. But if they continue to test PCR positive for days weeks, after covid-19 infection, very rarely does this actually mean particularly in someone who is not immunocompromised. So in a normal individual who do not have Amino compromising conditions that rarely does, this mean that they still have active infection, meaning that what we care about is whether or not the virus is still replicating. And that is what you need in order to be able to transmit the infection. And so initially you get the PCR test to know whether or not you as an individual has covid-19. But then we don't recommend routinely that you get a PCR test to see whether or not you had clearance of the virus because just because you might still test positive. All that means is that you still have a term we call to as shedding virus, mean that, You may still have RNA that can be detected in your nasal swab when they do that for a PCR test. But what it does not mean is that you necessarily have replicating virus, which is what you need to actually transmit the infection to others. That is why it is much better to do a rapid antigen test because those home rapid antigen test will only turn positive. If you have enough virus, that is usually is clinically significant meaning that it not only could cause you to In you to have symptoms, but also it can be show that you are then able to transmit the virus to others. Thank you."
The CDC recommends that people who test positive for COVID-19 isolate for up to 5 days, unless they are immunocompromised, in which case they should isolate for up to 20 days. People should also wear masks indoors around others until day 10. It is also recommended to take a second antigen test to ensure that the virus has been sufficiently cleared from the body. Transcript: "Hello. I'm Anne William and infectious disease. Specialist at Brigham Women's Hospital in. Boston, I'll be answering today. The question. This is a very important question. What are the current CDC recommendations for what to do? If you test positive or covid-19, so what we know is, if you do test positive for covid-19, you are at risk of transmitting it to others. So from a public health perspective, the CDC recommends that you isolate for up to 5 days. Minimum, if you An individual that does not have any immuno compromised in conditions, and therefore are less at risk for having ongoing viral replication beyond that time period. And so the minimum is five days of isolation and this changed a number of months ago, it used to be that you were recommended have a longer isolation period. But now with the ohmic on variant that has been shortened to 25 days. There are still many individuals who will still test positive. Buy a home rapid antigen test. Not a PCR test. East, but a home antigen rapid test and that then signifies that they still potentially have a high enough level of virus that could be transmissible to others. And so many organizations, many Hospital settings and other places will also recommend that in addition to waiting five days, assuming you have Improvement in your symptoms, that you also then do a repeat home. Antigen test to see if you test still positive and therefore should continue to isolate through till day 7 Day 8. Are up-to-date n, but if you don't, and you just wait the five days, then they are recommended to continue to wear a mask indoors around others up through day 10, because we do know that many individuals will still be contagious between days five and a 10. And so, if you are immunocompromised, however, the CDC guidance is that you were the you should isolate for a longer period of time and they should isolate up to 20 days from symptom onset. So all these recommendations for five days of isolation or 20 days of isolation, even if you're meaner compromise, is based on your symptom onset and ultimately then you should contact your primary health care provider to see, if whether or not you would benefit from one of the outpatient treatments for covid-19 and continuous supportive care to, make sure you don't need to seek medical attention and come to the emergency room if your symptoms were to worsen,"
Antivirals, such as Paxil Ovid and mono P. Revere, can be beneficial in preventing individuals from developing severe infection, or requiring hospitalization or death from covid-19. Those with other risk factors for severe infection, such as those older than the age of 50, those with cardiac risk factors, those who are immunocompromised, or those who are obese should be treated with antivirals. Transcript: "Hello and Willie here. I'm an infectious diseases, specialist at Brigham Women's Hospital in Boston, I'm going to answer a very important question. Who should be treated with antivirals in the setting of a covid-19 infection? This is a great question, very pertinent because we know we were all so happy with in the early 2020 to suggest less than a year ago, when the oral antivirals Paxil Ovid as well as mono P. Revere were approved because prior to that we only had access to IV. Antivirals REM Fear or we had monoclonal antibodies, which fortunately, we still have, but are also IV, formulation Semana para ver. Unfortunately, did not have a very high efficacy when in their clinical trial data and only showed a 30% reduction in ongoing preventing individuals from having ongoing severe infection. However, it still has a role for those individuals who cannot take Paxil obeyed because Paxil Ovid though, having a much higher efficacy of up to over 90%. Preventing individuals in the clinical trial from developing severe infection, or requiring hospitalization or death from covid-19. It has a protease inhibitor as part of the Paxil, Ovid medication is to medications to antivirals, one of which is a protease inhibitor that interacts with a lot of medications, some medications that your doctor can easily just have you hold and don't impact things. But other medications that are dangerous to take when you're already are on packs of when you are taking packs loaded because of the drug interactions of It can cause and so, therefore, those individuals need to be careful and not take packs loaded, or make sure you have a clear discussion with your doctor about the risk benefits of the medications you're currently on. But as far as who in now, a highly vaccinated society would benefit from Paxil Ovid. I would say those are the individuals that already have other risk factors for why they would go on to have a risk of having severe infection. So those are individuals that are older older than the age of 50. Those that have cardiac risk factors may be immunocompromised, or may be obese and have other independent risk factors for being considered higher risk for severe covid-19 infection and those I would definitely recommend it. I would say if you're on the fence I still would recommend it. We have not seen harmed with the antivirals and we see a lot of clear benefit and I think a big reason why we are seeing fewer and fewer hospitalizations due to covid-19 has a lot to do with the treatments were able to offer"