Dealing with Recent Spike in Dengue Cases

Ms Sylvia Lim asked  the Minister for the Environment and Water Resources (a) what steps, if any, are being taken to make the Sanofi dengue vaccine available in Singapore as soon as possible; (b) what timelines have been set for assessing the applicability to Singapore of controlling the mosquito population by infecting the male Aedes mosquitoes with the Wolbachia bacteria; and (c) what other methods are available in the pipeline and what resources are being committed by the Ministry to evaluating these other methods as counter-dengue measures.

There have been more than 12,000 reported dengue cases so far this year in Singapore. This current epidemic has actually been ongoing since 2013 and it is driven primarily by three factors. First, we experienced a switch in the predominant dengue serotype. Currently, it is dengue serotype Type 1. This dengue Type 1 virus spreads more rapidly than the other strains in Singapore and, in fact, now accounts for about 90% of all current infections. It is at a historic high. The second factor is that our population, in general, lacks immunity to dengue infection. This is a paradoxical result of our previous success, as a cumulatively low incidence of dengue in the past means, by definition, most of us would not have had prior exposure and, therefore, lack immunity. Third, the mosquito Aedes aegypti is still endemic in Singapore in spite of all our efforts over the past decades.

The dengue risk is amplified during the current hot season and this is because in times when the weather is hot, the maturation cycle of the mosquito accelerates and there is also a shorter incubation period of the dengue virus within the mosquito itself. Data from the National Environment Agency's (NEA's) 3,000 gravitraps which we have deployed island-wide has also shown a doubling in the population of adult Aedes aegypti mosquitoes since May 2014.

Consequently, source eradication, or the elimination of mosquito breeding, remains our primary strategy. This year alone, NEA has conducted more than 1.9 million house or premise inspections and deployed more than 1,000 gravitraps in dengue clusters for mosquito-control purposes, in addition to regular fogging and space-spraying in certain hotspots.

As Mr Zaqy Mohamad has noted, poor housekeeping at construction sites poses a dengue risk to both their own workers onsite, as well as residents in sites adjacent to the construction site. NEA has therefore increased inspections and taken stringent enforcement action against errant contractors whose sites breed mosquitoes. Sixty-two Stop Work Orders have been issued this year alone; 14 contractors have been prosecuted in Court and are liable for a maximum fine of $20,000 for the first conviction. Penalties have also been levied on homeowners, Town Councils and other landowners whenever breeding is found within their premises for which they are responsible. The fines levied this year have ranged from $200 for a home owner, all the way to $39,000 for a construction contractor. We will study

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the suggestion, which some Members have put up, for us to increase penalties further.

However, all Singaporeans must also continue to stay vigilant and we must keep our homes free of breeding habitats. We have found more than 4,000 breeding habitats in residential premises this year alone, in the first seven months and this shows that there is frankly, still quite a lot more that we can all do to reduce the risk for our own families and our neighbours.

NEA's Environmental Health Institute (EHI) is also working closely with international and local researchers to develop and evaluate new tools and new strategies to deal with dengue. One interesting proposal which we are studying right now utilises the Wolbachia bacteria. When a male mosquito infected with Wolbachia bacteria mates with a female mosquito, no viable progeny is produced. Hence, we are currently studying the feasibility of using such Wolbachia-infected male Aedes aegypti mosquitoes in order to suppress the overall population of mosquitoes in Singapore. I have appointed a Dengue Expert Advisory Panel which consists of both international and local experts to provide scientific advice to us on the safety and effectiveness of this technique in our local context. But as this is a novel biological intervention, I want to give you the assurance that we will not embark on field trials unless it is very clear that safety can be totally assured.

NEA also works closely with HSA to monitor the development of dengue vaccines and I think there has been some publicity on this recently. In fact, according to media reports, Sanofi, which is a pharmaceutical firm, has been conducting Phase 3 clinical trials in Southeast Asia. HSA will review the Sanofi vaccine with the appropriate experts when Sanofi applies for approval to market their vaccines later on. Once the vaccine has been approved and registered, it will then become available through the medical clinics and hospitals. However, I also want to caveat this point – that we will not approve vaccines unless we are sure it is safe and effective.

I want to end by saying that our NEA officers – every day, there are about 850 of them going around homes – they have been working very hard on the ground to create a safe environment for Singaporeans. I want to thank all the NEA officers. And I urge everyone here and outside this Chamber to support the officers and to do whatever they can and whatever we can, in order to protect ourselves and our loved ones from dengue.

I thank the Minister for his comprehensive reply. I also thank him for considering the heavier penalty fines. I have a number of residents who are also asking whether NEA would look into channels in which they can facilitate claims of

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medical fees and costs should there be construction sites and construction companies that have been found to be guilty of breeding mosquitoes and spreading dengue to the nearby housing estates. But more along the lines of public awareness, as I went around Chua Chu Kang – which had one of the record number of dengue outbreaks – I found that most of my residents were actually very aware of NEA campaigns and the five-step Mozzie Wipe-out, and if you go around, it is probably hard to find trace in flower pots, for example. They have removed these and have done all they can, but yet, 80% of the breeding sites are found in the homes. Is there a gap somewhere? Or are there some new developments that we have been missing and should be looking into? What more can we do, basically, to help this situation?

I thank the Member for the two supplementary questions. Let me deal with the latter one, which is what more can we do in our homes? In fact, you have hit the nail on the head, that it is often the areas which we take for granted, that are literally right in front of us, that we miss. Therefore, it calls for us to first, be aware, and I think the Member is right, people are aware that they are confronting a major epidemic. But to translate that awareness into regular actions in our homes, systematically comb through and look for those breeding sites, that part is much harder, because it requires everyone to do it.

We can have 850 officers, we can have 1.9 million inspections in seven to eight months, but it is not possible for NEA officers to be everywhere all the time. So, this is where I really require the assistance and the support of homeowners, contractors, Town Council officers and indeed all the Members in this House as well. One factor which we have found that helps is that the Member of Parliament takes a serious interest in this – walks the ground and mobilises people, to look in their own neighbourhoods, in the common corridors, in their homes. It does make a difference. I do not have any magic bullets; I do not have any easy solutions, but I need the cooperation of everyone in this House and indeed all Singaporeans.

The first supplementary question was on what further legal sanctions are available against errant contractors. First, let me put it this way: we have a legal regime. If they are breeding mosquitoes, we will hold them liable, we take them to court, we prosecute them. The standard of proof needed is as long as I can show that they were breeding mosquitoes, that should be sufficient for me to secure a conviction. I think the Member is asking to go beyond that. For a resident to be able to claim medical fees or indeed, compensation from an errant contractor, this is going to be far more problematic, because you would have to establish that it was failure to maintain proper housekeeping which led to that particular population of mosquitoes, which then were the key vector that resulted in infection in this specific individual. That is a much harder level of proof. I am not aware of any case that has yet succeeded in Court.

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I need to emphasise that even if the breeding or the infection has been amplified in a construction site, in order for it to keep going, it requires that there was breeding of mosquitoes in the surrounding residential homes. So, again, it brings us back to the point that we all need to exercise vigilance in our own homes. It is not enough to just point fingers at the contractors, or indeed, just to point fingers at your neighbours. We all need to do our part, and if we all do our part, I think we can make a difference.

Thank you, Madam. I note the Minister's point that he is reviewing whether to increase penalties for mosquito breeding. But I would like to point out that there is a difference between water trapped in the laundry pole-holder and stagnant water in an ill-maintained and unused private swimming pool. Hence, the difference in potential of mosquito-breeding in these different water bodies. Also, with a smaller volume, there is probably a higher concentration of mosquito larvae, leading to easier detection upon inspection by NEA officers. Would the Ministry consider tiering the penalty fees to better reflect the different risks posed by poor housekeeping, according to different scales, even within residential homes?

I think that is a reasonable suggestion, which I will study.

Mdm Speaker, I would like to ask the Minister if he would consider making known the list of pest control companies that are involved in the construction sites that have been found to be breeding mosquitoes. This is something like a black list so that people will know who are the ones who did not do their jobs well. They are supposed to check every week and take action.

Secondly, these pest control companies use a lot of low-skilled and foreign workers. I wonder what is the training regime for these workers. Is there constant training for these workers to do their job right?

Madam, I thank the Member for that question. First, there is a training regime. In fact, all the workers engaged in vector control have to be licensed and we have to ensure that methods which they are using are safe for themselves – because they will be exposed to chemicals – as well as for the residents nearby. So, there is a regime in place.

I take the Member's first point about whether there should be greater transparency. So, if we find mosquito breeding in construction sites, we must know who the developer is, who the contractor is, who the subcontractors are and which vector control companies are

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involved. I think this is something worth studying in greater detail.

The Minister mentioned about some vaccine from Sanofi. But there was one announced recently in the newspapers on 31 July 2014. It is called Celgosivir and supposedly, it is derived from natural compounds. Can the Minister elaborate on this and are we looking at this and accelerating the development of this vaccine?

I thank the Member for that question and I beg the indulgence to give a bit of medical details. First, on the vaccine. The media reports were about the Sanofi vaccines. A multi-centre Phase 3 trial was conducted in children in various parts of Southeast Asia. It showed some promise, but to be honest with you, my frank opinion is that it is not good enough. Why do I say that? It showed reasonable effectiveness – about 75% for Type 3 and Type 4 serotypes of dengue. Against Type 1, which is the current problem we are having, it was only about 50% effective. Against Type 2, it was only about 35% effective. Those rates of efficacy are not, in my opinion, good enough. There is a further theoretical risk with incomplete vaccination. The theoretical risk is that if you have had prior infection, or if you have prior immunity to one of the four serotypes and you get a second infection with a different serotype, there is a theoretical risk of you having a higher chance of contracting hemorrhagic fever or shock syndrome.

Until further clinical data is available for us to be sure that the benefits outweigh the risks, I do not think MOH and HSA will rush into approving the vaccine. I think the precautionary principle has to apply and that is why, although I agree with the Member, the long-term solution to dengue is a vaccine. We need to spend more work to get the right vaccine out there and then assure ourselves that it is safe before we can issue it. In the meantime, it is the hard, laborious work of source-eradication and the hard work that our officers embark on.

The other report the Member referred to was the use of this anti-viral material called Celgosivir, which is derived from a plant. In fact, some of our local researchers have done some studies on that. Again, these are very, very early days. I think they are only in Phase 1 trials, which means establishing whether it is safe or not. They have not gone on to prove efficacy, that means whether it is effective.

I am glad that we have a reasonably good research, scientific and medical community in Singapore which is focused on this. But I want to say that it would be premature to conclude that we can rely on vaccines and anti-viral medications to solve our problems. For the foreseeable future, which is for now and for the next couple of years, we need to all work

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hard on the ground to eliminate mosquito breeding.