MANILA, Philippines — Dengue fever cases dramatically decreased through the COVID-19 pandemic, however the tropical disease remains a threat to the Philippines, particularly through the wet season, with outbreaks all the time a risk.
“We need a vaccine for dengue,” Dr. Lulu Bravo, a vaccine expert, instructed INQUIRER.internet in an online interview on Wednesday, the final day of June, which was National Dengue Awareness Month.
“Vaccines, are the ones that can control, prevent and hopefully, eliminate, and last but not the least, eradicate the disease… Only the vaccines can do that,” Bravo added. “Without vaccination, any disease will come back, until such time the disease will get eradicated.”
Bravo is a professor emeritus of the College of Medicine on the University of the Philippines-Manila, a steering member of the Asian Dengue Voice and Action (ADVA), government director of the Philippine Foundation for Vaccination.
There are presently no dengue vaccines out there in the Philippines for the reason that Food and Drug Administration (FDA) completely revoked the certificates of product registration of Dengvaxia, which is manufactured by Sanofi Pasteur.
The vaccine figured in controversy after being linked to the deaths of several young children who had been inoculated with it.
Dengvaxia was the primary dengue vaccine to be licensed, in line with the World Health Organisation (WHO). It is has been accredited for use in 20 nations, together with the United States and Thailand.
“It’s really unfortunate, with what happened with Dengvaxia. It is a good vaccine,” Bravo mentioned.
Still, the nation’s dengue incidence has remained manageable to this point.
Dengue by the numbers
The Department of Health (DOH) reported a steep drop in dengue cases and deaths for the primary quarter of 2021.
There have been solely 21,478 cases of dengue from Jan. 1 to April 17 — a 56 p.c lower from the 49,135 cases reported in the identical interval final yr.
As for deaths, solely 80 deaths have been recorded for the identical interval — 55 p.c decrease than the 179 deaths recorded in 2020.
In 2020, there have been a complete of 83,335 dengue cases, with 324 deaths — 81 p.c decrease than in 2019 when the DOH declared a national dengue epidemic.
There have been 437,563 reported dengue cases with 1,689 deaths in 2019.
The DOH attributed the lower of dengue to the heightened well being consciousness of the individuals through the COVID-19 pandemic and the observe of the so-called 4S technique — search and destroy breeding locations, search early session, self-protection, and help of fogging and spraying in hotspot areas.
“You know the pandemic actually maybe had reduced [the cases] because people were not going outside,” Bravo mentioned. “But still we are kind of vigilant because the coming of the rainy season means that the incidence of dengue is going to be high.”
“Because you know, masking, face shield, and even distancing will not control dengue because this is really brought by mosquitos,” she added.
Dengue and vector management
Dengue, although not a communicable disease, is unfold by virus-carrying feminine mosquitoes of the Aedes aegypti and Aedes altropicus breeds. Only feminine mosquitoes chunk people and unfold the virus.
According to Bravo, feminine aegypti mosquitoes are distinguished by the white and black stripes on their tails.
Bravo mentioned that dengue prevention had all the time been primarily based on “mosquito vector control.”
Vector management is any methodology to restrict or eradicate animals, like mosquitoes, that transmit pathogens — that’s, disease-causing microorganisms.
Among the commonest mosquito vector controls carried out in the nation are cleanup drives that concentrate on draining clear stagnant water in inhabited areas the place mosquitoes are prefer to breed.
“This Aedes aegypti, which is the mosquito species that is carrying the dengue virus, likes to breed in clean waters, not dirty canal waters,” she mentioned. “As long as it is cleaner than ordinary canal water, it would be there.”
Another type of controlling the mosquito inhabitants is thru fogging, however Bravo mentioned it’s not efficient.
“It doesn’t really reduce the number of mosquitoes,” she mentioned. “Unfortunately, it just drives the mosquitoes towards the next neighborhood.”
Bravo revealed, nonetheless, a latest breakthrough in lowering vector management in the type of the Wolbachia micro organism that current in many bugs species.
These micro organism compete with viruses – like people who trigger dengue, zika, chikungunya, yellow fever. They make it laborious for viruses to breed inside mosquitoes, in line with the World Mosquito Program (WMP).
“By breeding mosquitoes that carry safe and natural Wolbachia bacteria, we can effectively prevent diseases from spreading in whole cities and even regions,” in line with the WMP website.
To measure the efficacy of the Wolbachia methodology, the WMP performed a cluster randomized managed trial in Yogyakarta City, Indonesia.
In June 2021, the New England Journal of Medicine printed the peer-reviewed outcomes of the trial, which revealed that Wolbachia-treated areas had proven a lowered dengue incidence by 77 p.c and dengue hospitalizations by 86 p.c.
Bravo has a caveat, nonetheless.
“But I don’t think they will be able to eradicate mosquitoes,” she mentioned. “Mosquitoes have been here for millions of years.”
“The use of the vector control, the preventive measures, all the cleanup, the fogging we have done in the Philippines for the past how many years now, and we have not actually decreased the incidents,” she mentioned. “In fact, it has increased and has become a global threat.”
“So with that, you can see that dengue is to be controlled and prevented, and the only way we can do that, just like so many diseases, is through vaccination,” she added.
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