Asia’s
first dengue vaccination programme has been launched and is picking up steam in
the Philippines despite misgivings in some local health quarters.
The
Philippines became the first Asian country to license Sanofi Pasteur’s dengue
vaccine, Dengvaxia, last 22 December, following Mexico’s approval of the
vaccine on December 11.
Dengvaxia
is a tetravalent vaccine taken in three shots at six-month intervals and is
recommended for individuals aged 9 to 45. The challenge with dengue is to
develop a vaccine that is safe and effective against all four dengue strains.
Dengvaxia is assessed to be 90 per cent effective.
Three
Philippine government ministries — the Department of Health (DOH), Department
of Education, and Department of Interior and Local Government — collaborated in
a major launch of the vaccine in Metro Manila on 4 April. [1]
President
Benigno Aquino III was also present when DOH secretary Janette Garin
administered the injection on one of the first children to be vaccinated.
Questions about prequalification
The
Philippines went ahead with the school-based mass vaccination programme even
before it was prequalified by the WHO. Prequalification is a standard procedure
by WHO to ensure that vaccines purchased by the UN and government procurement
agencies are safe and effective.
This has
led some medical doctors to raise doubts about the early launch of the mass
vaccination programme. The doubting doctors include Teodoro Herbosa, former DOH
undersecretary, and Anthony Leachon, board member of the Philippine Health
Insurance (PhilHealth). They oppose the implementation of the DOH’s 3-billion
peso (US$64 million) mass immunisation programme without WHO prequalification.
However,
the WHO Strategic Advisory Group of Experts on immunisation has reviewed
Dengvaxia (CYD-TDV) in April 2016 and recommended introduction of the vaccine
in countries or places where dengue is endemic even while awaiting WHO
prequalification.
One post-vaccination death reported
As of 24
April, the DOH has vaccinated 204,397 students in grade schools in the Manila
metropolis, out of the 279,393 students whose parents have expressed consent to
the vaccination. [3]
The DOH
reported 362 cases of Adverse Event Following Immunisation (AEFI). This is
medical jargon for side effects to the vaccine, which include fever, headache,
dizziness, vomiting and rashes.
The
percentage of students that developed side effects, however, is minuscule —
less than one percent of the total number immunised.
The death
of an 11-year-old boy was reported after his immunisation on 31 March although
he was screened and assessed by a health doctor before vaccination. He
developed fever and diarrhoea on 3 April. He was in and out of different
hospitals following that, experiencing difficulty of breathing, fever and
cough. He was diagnosed with pneumonia, severe congenital heart disease and
electrolyte imbalance. On 11 April the patient had cardiac arrest.
The case
was presented to the DOH National Adverse Event Following Immunization
Committee for review, after which the committee said it was coincidental that
the boy had cardiac arrest after immunisation.
WHO support
The WHO
has endorsed the decision of the Philippines to go ahead with its dengue mass
vaccination programme based on its own scientific appraisal of the clinical
research that preceded adoption of the vaccine.
The WHO
country representative in the Philippines, Gundo Weiler, said in a press
conference, that they support the Philippine dengue vaccination programme. [4]
Weiler
explained that WHO’s Strategic Group of Experts on Immunization meets twice a
year to vet new medical products like drugs and vaccines and advise WHO on what
products to approve. The WHO formal prequalification guidelines and
recommendations on the new dengue vaccine are expected to be released in May.
Dengue vaccine pioneers
The
Philippines is the first country to implement dengue vaccination in schools and
aims to immunise one million grade school children aged nine years and above in
the next few years.
Dengue is
highly endemic in the Philippines. It ranked first in highest dengue incidence
in the Western Pacific region from 2013 to 2015.
There are
some 400 million dengue virus infections globally each year. The Asia-Pacific
region has the highest incidence of dengue in the world, accounting for more
than 70 per cent of dengue cases. South-East Asia alone had an average of 2.9
million dengue cases and 5,906 deaths from 2000 to 2010. [5]
The
Philippines has taken a bold step to try this new dengue vaccine in Asia on
such a massive scale. It joins only two other countries so far, Mexico and
Brazil in South America, in daring to be among the pioneers.
In the
face of data that dramatise the dengue danger, Philippine health officials have
decided it is worth taking the risk. The reward looks to be great — a defense
against a disease that is not to be taken lightly. The next steps should be
against the Zika and Ebola viruses.
Crispin
Maslog
Crispin Maslog is a Manila-based consultant for
the Asian Institute of Journalism and Communication. A former journalist,
professor and environmental activist, he worked for the Press Foundation of
Asia and the International Rice Research Institute.
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