Professor David Hui, director of S.H. Ho Research Centre for Infectious Diseases, Stanley Ho Professor of Respiratory Medicine and the Chairman of Department of Medicine and Therapeutics of The Chinese University of Hong Kong, is on the show this year, to talk about influenza prevention and debunk the virus for us, and to talk about the dos and don'ts in order to prevent getting ill.  

Check out the full transcript of TVB’s Straight Talk host Dr Eugene Chan’s interview with Professor David Hui:

Chan: Good evening! This is Eugene Chan. This week on Straight Talk, we are joined by Professor David Hui. Professor Hui is the director of S.H. Ho Research Centre for Infectious Diseases, Stanley Ho Professor of Respiratory Medicine and the Chairman of Department of Medicine and Therapeutics of the CUHK. He joined the World Health Organization as advisor on influenza outbreak and served as an advisor to the Hong Kong Special Administrative Region government on COVID. He was one of the top 1 percent of highly cited researchers worldwide. Let's hear his sharing on the recent influenza surge in Hong Kong and globally. Welcome, David!

Hui: Hello!

Chan: Professor, you know, Hong Kong recently has seen a surge in influenza cases, with many contracting the flu after returning from holiday trips to Japan and Korea. We previously thought that flu only kills those people who may be old or immunocompromised. I read the news that the death of a famous Taiwanese actress and singer Barbie Hsu, “Big S”, due to influenza at the age of 48, was quite alarming. So, why would the flu kill and which are the susceptible populations?

Hui: Well, the winter outbreak in Hong Kong actually started on the fifth of January this year, and by the 12th of February, we actually have lost 186 adults, they died of flu, and we also had about 301 fatal or severe cases. Now the majority, more than 70 percent actually did not receive the seasonal influenza vaccine before the season, and 70 percent of these people also have chronic illnesses. So, these are the predisposing factors, and among the 186 people who died, 90 percent or more are actually aged 65 years plus elderly. So, those who are susceptible include old age and also young age, below the age of five, the immune system is immature. Those who are 65 years old or more, the immune system is ageing.

Chan: Right. So, when do we bring that fact up earlier? So, how common is the case of, say, Barbie Hsu? I mean, she's only 48.

Hui: Whereas I heard from the media, she did not receive the influenza vaccine to begin with, and she also appeared to have some chronic illnesses, including epilepsy and also a heart valve problem. So, these are the chronic illnesses that may also increase the risk of severe diseases.

Chan: You just mentioned we have 186 cases from January to February. I mean, to me, it's quite alarming, because, I mean, I'm sure we have unfortunate cases of people leaving us, but due to the flu, most people should be alarmed. Should we be alarmed?

Hui: Well, this is preventable. So, before the beginning of the season, one should really receive the influenza vaccine. So, in Hong Kong, it is recommended that anyone aged six months plus, should receive the seasonal flu vaccine, and those who are at higher risk should be given the priority, like young children, elderly aged 65 years, plus those who have chronic illness, those who are immunocompromised, in pregnancy and healthcare workers.

Chan: So, you advocate sort of a universal flu vaccine?

Hui: Well, the high risk group should be given the priority, but then if, for people who like to travel, they should also receive the vaccine.

Chan: Alright. Is there something new in the flu strains that make people, more I mean, susceptible?

Hui: According to the analysis, the circulating strains at the moment match very closely to what are contained in the vaccines. So, this is actually a good match this year.

Chan: Right. I mean, I had some medical knowledge before, and I know that the virus does mutate, there are variants all the time. I mean, it's good to know that the current vaccine is sort of very appropriate. But how can somebody know that they won't contract some sort of virus that doesn't match your vaccine and then you still get infected?

Hui: Well, the virology lab, they always do the monitoring. So, if there's any new virus, a new strain that has mutated, it will be found out on the sequencing. But in the current season, we know that the circulating strains match quite well with the vaccine strain.

Chan: Right. Do we have enough vaccine stock in Hong Kong to allow the full population's vaccination?

Hui: Well, so far, about close to 2 million people in Hong Kong have received the vaccine. The government actually has stocked quite a good amount. And also there are also quite a fair bit in the private market.

Chan: Yeah, since you're on the show where I'm sure the viewers would love to hear from you the expert, what are the signs of symptoms of the flu? Because often people say, I'm not feeling it very well. I feel tired. Someone said, oh, I only have a common cold. So, how can we tell whether I have the flu or I do not have the flu?

Hui: Well, people who have the flu usually have a fever, sore throat, runny nose, and cough. Also they have muscle pain, joint pain, they feel tired. The unlucky one may develop pneumonia, so they get short of breath. And also the unfortunate children, some of them, may develop central nervous system involvement, called encephalitis, so they get drowsy, heady, etc. For the common cold, it's a lot milder. Usually, you get some nasal congestion, sneezing, cough and usually self-limiting. Within three to four days, you get better. The etiology is different. The common cold is usually due to rhinovirus or the common coronavirus. Whereas influenza, we have four types: H1N1, X3N2 and also two types of B.

Chan: So, if someone had a flu vaccine, does it prevent him or her from getting the cold? It doesn't, does it?

Hui: Well, the influenza vaccine only prevents four types of influenza – H1N1, X3N2 and the two types of B virus. It does not prevent against other viruses, like rhinovirus or other coronavirus, etc.

Chan: Is there any vaccine for the common cold as well?

Hui: Unfortunately, there's none.

Chan: Right. Okay, so when you talk about, I remember when we had COVID, we did have all these tests, and now we also have tests available on the market. So, do you still diagnose patients with such kits, or you just based purely on symptoms and signs?

Hui: Well, we do look at the rapid tests which are readily available these days. So, some actually, some tests can actually test for six to nine types of different viruses, but you need to have quite a high viral load in order to be tested positive. So, the sensitivity for the rapid test is not the best. In the hospitals. I think we look at the PCR, which is a lot more sensitive, reliable.

Chan: When you think about it. I mean, if somebody already has a lot of symptoms, does it matter which type of virus he or she is contracting, in terms of treatment?

Hui: It does. It does. So, if you have influenza-like illness and if your rapid test is positive, and if you do have high-risk factors like age, chronic illness, immunocompromised, etc, but if you are tested positive for influenza, there are medications that can help prevent progression of the disease.

Chan: Right. So, Professor, so what you're saying is, if you're age 60 or above, if you are immunocompromised, or have long-term illness, it is a very silly thing not to have vaccinations. And even if you have some sort of symptoms, you should have a test to find out what type of flu you are getting, so they get the right treatment. Am I right, so far?

Hui: Yes, you are right. Yes, those who have risk factors, if they are tested positive for influenza early, then nowadays, they are oral antiviral agents that can prevent the progression to severe disease and death.

Chan: Yeah, we will be moving along that for the next part of the show. So, for people who do travel, do we have to take extra precaution, especially as I said earlier, because our friends come back from Korea and Japan, they often come back with flu. So, if they had the vaccine, would that prevent them from catching a flu overseas.

Hui: First of all, they need to have the vaccines two weeks before the holiday.

Chan: Oh, two weeks before.

Hui: Yes, it takes two weeks to build up an antibody. Now, the vaccine is not 100 percent protective. Overall, there is actually vaccine effectiveness of about 40 percent to 60 percent in preventing the influenza infection during the seasons.

Chan: Right, 40 percent to 60 percent?

Hui: 40 percent to 60 percent, yes.

Chan: Anything else we can do to minimize catching a flu? Wearing a mask on the plane, is it a good idea?

Hui: Yes, exactly. If you travel in very crowded areas, like on the plane, in the airport, taking public transport, where there are lots of people, it would be advisable to put on a surgical mask to prevent the droplet inhalation and also pay attention to your hand hygiene, because sometimes you may touch the fomites, rub your nose, rub your eyes.

Chan: So, everything we learned during COVID applies.

Hui: Exactly, they are applicable.

Chan: Right. So, there's a reason why we see people traveling on MTR or even on the plane wearing a mask. We shouldn't be looking at them with a frown, should we?

Hui: Well, I think we should respect them. They do have the knowledge to prevent themselves.

Chan: So, maybe we should be wearing ourselves.

Hui: Exactly, exactly.

Chan: Alright. Let's take a short break now. We will be right back.

Chan: Thank you for staying with us. Professor David Hui, the director of S.H. Ho Research Centre for Infectious Diseases of the CUHK, has been sharing with us about the recent surge in the flu in Hong Kong and globally. So, Professor, I think what you have said is that we have to be careful, especially after learning all these good practices from COVID, that flu is actually preventable to a large extent. Am I correct in that statement?

Hui: Certainly, it is one of the preventable respiratory infections.

Chan: Right. So, we must take the vaccine, give yourself two weeks for it to be effective. It should, say, prevent 40-60 percent of the flu, did you say?

Hui: Yes, it reduces your chance of getting the infection by 40-60 percent. And even if you do get it, it will be a lot milder compared to unvaccinated.

Chan: And wearing masks as well …

Hui: Yes ... on public transport, a lot of people.

Chan: Right. So, having with all that knowledge in our mind, in what situation that we should go to the hospital, or even see a doctor, or even go to the actual emergency?

Hui: Now if you do have persistent fever and also feeling short of breath, then you need to watch out for pneumonia. The virus might have gone down to the lower respiratory tract, causing bronchiolitis or even pneumonia, so that will cause shortness of breath. For the children and some adults, if they become drowsy, not arousable, with headache, you need to watch out for central nervous system involvement, especially brain infection, encephalitis. So, if you have any of those symptoms and signs that I mentioned, you need to seek medical attention early.

Chan: I see. So, a lot of people say that “Oh, I am just having a cold or I am just having a flu, I am going to sleep through it”. So, is rest mandatory for flu recovery? Or even if you take no medication, is it going to sort of, is it a self-limiting disease, as you said, rightly pointed out?

Hui: For the majority of people, rest and enough sleep are certainly very important. Yes, so usually it will be gone by about 5-7 days, for most people. But then there are also people who are unfortunate enough to develop complications, such as pneumonia or encephalitis.

Chan: Right. So, what you are saying is the best is with medication and a lot of rest, but what if you have to work or study, what would you recommend those … How would you sort of minimize your symptoms and sort of not have such disruption to your life?

Hui: Well, the most disabling symptoms are, you know, cough and nasal congestion. So, you need to … and also fever, of course, so you need to get the medication from the counter to settle the fever and also to decongest the sinuses. And also after influenza, very often there is a period of what we call post-nasal drip. Your sinuses are full of fluid, and it keeps going backward, causing itchy throat and cough, and that may last for a couple of weeks. So, you need to get some antihistamine, and also some nasal decongestant, so that will help ease the symptoms.

Chan: Right, and what about hydration? I mean how important is it during recovery? Should we drink a lot of water to help?

Hui: Well, hydration is also important because when you have fever, you tend to evaporate more water, so get dehydrated. So, adequate hydration, adequate sleep and rest are very important.

Chan: Right, before we move on to antiviral medication, I want to ask you a lot of people who say, “All right,, I have this cold once or twice a year, I am going to sleep through it, I am going to buy some medication from the dispensary or pharmacy that will work”. Do you think that is a good practice?

Hui: Well, you may stock some, what we call, safety medications. So, like the antipyretic medication that can lower fever, medication that can decongest your sinuses, cough compound. Those are useful at times. But if you do have other symptoms, like shortness of breath, getting drowsy, etc., then you should seek medical attention early.

Chan: Right. You mentioned that with flu, you have four or five types of virus …

Hui: Four types … four of virus.

Chan: So, antiviral medication could be useful. And we know there is a new drug called …

Hui: Xofluza

Chan: Xofluza, and people say that you only need to take 1 or 2 tablets of Xofluza at any type of the illness, whereas the older drug, like the other drug, Tamiflu, we have to take it for a whole week and it is only effective if it is taken within the first 72 hours of symptoms. Would you say this Xofluza is the drug for patients now?

Hui: Now we have 2 types of antiviral for influenza. Tamiflu has been in the market for quite a fair while, and there are also a lot of data showing that it can actually reduce mortality and decrease progression to more severe diseases. So, the WHO actually has recommended the use of Tamiflu for hospitalized patients. Xofluza is quite new, it blocks a different enzyme as compared to Tamiflu. The data are more in favor of people who have mild influenza in the community. But they do have risk factors. So, if you have like, being elderly with chronic illness, you take the Xofluza. It can also prevent progression to severe disease. And the advantage is you only need to take 1 tablet, whereas if you take Tamiflu, you need to take 5 days, twice a day for 5 days. Right, but this Tamiflu has better efficacy for hospitalized patients.

Chan: Right, I also read that Xofluza is good for prevention as well. So, it looks like this drug is a magic drug. So, should everyone with flu take this drug?

Hui: Now, it really depends on whether you do have influenza, okay? A lot of the viruses may cause similar symptoms. So, first of all, you need to establish by either rapid test or PCR whether you do have influenza. And if you do have influenza confirmed, then for those who have risk factors, like age, chronic illness, they may benefit from taking the medication. But if you are otherwise quite healthy and young, you may not need to take the medication at all. You know you will get over it in a few days.

Chan: Right, so Professor, you have given us sort of a cookbook recipe of what to do. We must or should take vaccines.

Hui: Yes.

Chan: And give enough time when you travel. And you have to put your mask on when appropriate, and watch your hands hygiene, and also go to the doctors at the right time. Let's move on the area like prevention. What can we stop the spread of flu? And is there specific dos and don'ts you can just add to what I have said earlier?

Hui: Now if you do have influenza like illness, first of all, don't go to work or don't go to school.

Chan: If you can help it.

Hui: Yes, and also do some rapid tests at home and see whether you have the influenza virus. If you have shortness of breath and also getting a bit headache, persistent fever, then seek medical attention early.

Chan: Early.

Hui: Yes.

Chan: And do you think our current health, public health measures in Hong Kong is adequate to address the recent surge in cases, especially we have 186 deaths? And maybe more proactive strategies should be used?

Hui: Well, in Hong Kong, the influenza vaccination rate is suboptimal. If we look at the risk populations, those 65 years plus, we only have an overall vaccination rate of about 49 percent. And the majority are actually in the nursing homes. Nursing homes vaccination rates are very good, 80 percent plus.

Chan: Right.

Hui: But in the community, a lot of elderly have not received the vaccination. The other risk group is the younger age, 6 months to 2 years. And so far the vaccination rate is only about 22 percent. So, these are the high-risk group that may also develop severe disease. The Department of Health actually has opened up the Maternal and Child Health Centre to facilitate the vaccination. We do need to encourage parents to bring the young children to these Maternal and Child Centres to receive the vaccinations. And also encourage the community, elderly, to receive their vaccinations because they are the ones that are prone to severe disease and death.

Chan: Professor, I mean after the news of celebrity Barbie Hsu’s death from flu, and especially after watching our show tonight, I am sure there will be even a higher surge in the amount for vaccinations. And I have heard that there is. Actually, the vaccines is out of stock at many clinics. So, what can we do to get the vaccines earlier? Can we go to the government or what shall we do?

Hui: Well, every year the government stocks a certain amount. I think the recent news of the celebrity who passed away due to flu increased the public awareness. So, people now, they go for the vaccines. I think the government and also the private sector, they can actually order more stock from overseas.

Chan; Right, so we should not be too worried.

Hui: Don't panic.

Chan: Right. The last area I want to just touch base on, as we know that a lot of people, the reason why they don't go for vaccination is they are always concerned about the little pain associated with that jab. As for young children, maybe afraid of injections as well. So, are there any developments such as oral vaccines? I mean, how effective are they? Are they just for the children or are they for adults as well?

Hui: Well, there are two types of vaccines available for seasonal influenza. We have the conventional intramuscular injections, which are made from the inactivated whole virus vaccine. The only side effects are really mild fever and injection site pain. That usually lasts for about 2 days or so.

Chan: Right.

Hui:  And nowadays we use very fine needles, so the pain is actually quite minimal. The other type of vaccine is the nasal vaccine. The nasal vaccine uses attenuated virus, and it is available for people who are aged 2 years to 49 years. But because you go through the nasal passage, if you have unstable asthma, you cannot use it because it contains attenuated virus, people who are immunocompromised or pregnant cannot use it. But otherwise, the people aged 2 to 49 years can also use the nasal vaccine.

Chan: How about oral vaccines?

Hui: So far, there are no oral vaccines available. I think they are under research.

Chan: So, Professor, thank you very much. That is all the time we have for this evening. And thank you so much for sharing your insights on flu and the important aspects of management and prevention. Thank you for joining us. Stay healthy and have a good evening!