KARACHI: As the government attempts to tackle multiple outbreal(s of vaccine-preventable diseasesinthe province,expertshave called for a probe into the efficacy of diphtheria vaccine currently being used for prevention against the highly contagious bacterial infection.

The experts have also emphasised the need for increasing the immunisation coverage age-bar (currently one day to two years) to five years a recommendation long overdue given the fact that a large number of children fail to get their vaccine doses at the age speciSed under the Expanded Programme for Immunisation (EPI).

Sources said while the cases of measles have declined significantly in recent weeks, the cases of diphtheria are on the rise,particularly in Karachi.

According to the experts, although both infections are vaccine-preventable, the fatality rate in diphtheria is much higher around 30 to 40 per cent in unvaccinated younger children.

According to the EPI data, 55 children died of diphtheria in 2023with three outbreaks reported in Karachi`s Central, East and Keamari districts.

Thisyear,ofñcialshave declared death of at least 40 children with outbreaks reported in Karachi`s West, Keamari and East districts, as well as Larkana and Dadu.

Surprisingly, however, the department has confirmed only 30 diphtheria cases out of the `219 suspected cases reported this year` `This wave of outbreaks continuing since 2023 indicates lack of timely action. Second, surveillance ofñcers are reportedly discarding diphtheria cases where the cultures [for isolating the bacterium] are positive but the toxin production [another test] is negative,` shared a senior doctor at a private hospital.

Severity of situation According to sources, 20 children -most of them aged between three and 10 years have so far died of diphtheria this year at the Sindh Infectious Diseases Hospital and Research Centre (SIDH&RC) alone in Karachi.

Over 80 diphtheria patients with the infection have been admitted to the same hospital during thecurrent year.

Source said that at present 16 children with diphtheria are under treatment at the hospital, which is one of the few government-supportedhealthfacilitiesin the province where the antitoxin required for treatment is available.

`For the time being, we can`t take other patients,` shared a doctor at the hospitalon the condition of anonymity.

At the Aga Khan University Hospital (AKUH), the sources said six children died of diphtheria three in April and as many in September out of the 17 patients admitted for treatment during the period between January and October 15 this year.

Last year, 27 diphtheria patients were admitted to the hospital.

At the Dr Ruth Pfau Civil Hospital Karachi, three children have died from diphtheria this year. A total 27 patients with diphtheria were admitted to the hospital this year.

At the Indus Hospital, diphtheria has claimed one life so far this year.

`Measles cases have declined significantly while diphtheria cases are increasing. While most of these cases constitute either unvaccinated or partially vaccinated children, we have also seen children who got infected despite getting three doses of the diphtheria vaccine [under the EPI programme],` said Dr Samina Junejo, senior paediatric infectious diseases consultant at the Indus Hospital.

She emphasised the need for investigating the efficacy of the diphtheriavaccine.

`The two booster doses [needed for better immunity levels under the WHO guidelines] are not part of the EPI programme,` Dr Junejo said.

A major barrier to providing treatment, she pointed out, was the acute shortage of the antitoxin. `There is still a shortage and we are forced to refer patients to hospitals where the diphtheria antitoxin is available.

Diphtheria`s comeback Explaining the gravity of the public health crisis triggered by diphtheria`s outbreaks, Dr Khalid Shafi of the Pakistan Paediatric Association said the disease had staged a comeback after 30 years and that there was hardly any case of the infection before 2023.

`Even a single case of diphtheria is unacceptable and alarming. The infection is highly contagious with ahigh fatality rate to up to 40pc [in unvaccinated younger children],` he said, adding that measles was endemic to the region and affected the population even in developed countries.

He recalled that experts had recommended that the age-limit for EPI coverage should beincreased to Eve years from zero to two years.

`Given the parental attitude, we will always have a significant number ofunvaccinated kids in pockets, [serving as host to pathogens and spreading infection].

Big catch-up drive Responding to concerns, EPI Director Dr Naeem Rajput said 76pc of the suspected cases were reported in children over Sve years of age, representing the cohort when EPI Sindh`s vaccination coverage was only 37pc.

`Our coverage has improved significantly, now at 70pc according to third-party assessments. Fifty-seven per cent of the suspected cases of diphtheria were in children who had not received any vaccine doses,` he explained.

The government, he said, had launched vaccination campaigns in the affected union councils and 678 children under five so far had received the Penta vaccine, while 1,042 children over five years old have been administered the Td (teta-nus, diphtheria) vaccine.

On the shortage of diphtheria antitoxin, he said the EPI had released 442 vials of diphtheria antitoxin to healthcare facilities across Sindh including the Indus Hospital.

`We have requested additional supplies from the WHO and Unicef, which are expected to arrive soon. In the meantime, mop-up vaccination activities continue in affected districts, particularly targeting children who have missed their Penta doses, which include protection against diphtheria.

About the overall improvement in the EPI programme, he said the government would be launching a big catch-up vaccination drive soon for under-five children who had missed their doses while a proposal was under consideration to include diphtheria booster doses in the EPI programme.

`Also, we are trying to increase the number of vaccinators, whose number currently stands at 3,500 while the province needs 12,000 vaccinators. But, our efforts couldn`t succeed without parents` support.

Right now, there are 250,000 cases of refusals in the province. This negative parental attitude has to change if we want save our children`s lives, he said.

He rejected reservations over the vaccine`s efficacy and said such statements lacking evidence would lead to `more vaccine hesitancy`.