Islamabad: As influenza A, particularly its H1N1 strain, has started infecting people across the country, infectious disease experts and pulmonologists have urged the public to take precautionary and preventive measures, including vaccination against flu. Genuine flu vaccine, however, is not available in the country, while the market is flooded with spurious and smuggled vaccines purporting to be of two multinational companies, they said.
In the absence of the multinational companies’ vaccines, the experts said, the better option was to opt for Chinese flu vaccines, as there is no credible scientific evidence that licensed Chinese inactivated influenza vaccines give less protection than their Western counterparts. The countrywide shortage of genuine vaccines has raised questions about whether Chinese brands can serve as a reliable alternative.
The question has gained urgency because vaccines of multinational companies, including Abbott’s and Sanofi’s, are currently not available in the market. Abbott’s vaccine might not be supplied this year, while Sanofi’s might arrive in limited quantity at the end of November or in December.
Importers and distributors of flu vaccines confirmed that Chinese vaccines, including those of Sinovac and Shenzhen Innovax, were also out of stock after their limited supplies were exhausted, but added that both vaccines would be available in ample quantity in the coming weeks.
Acting Director of the National Institute of Health (NIH) Islamabad, Dr Muhammad Salman, said Sinovac was now a known vaccine manufacturer and its product should be reliable and comparable with those of other manufacturers.
Dr Salman said Sinovac’s technology was the same as that of Sanofi’s vaccine, and that it was in line with the World Health Organization’s (WHO) recommendations for the northern hemisphere, with three influenza virus strains and the same dosing for this season.
Given its availability and cost-effectiveness, he said, it was a good alternative that could be used if there was urgency for vaccination, especially among high-risk groups. Scientifically, he said, Sinovac offered comparable protection, although he could not comment on other Chinese vaccines available in Pakistan.
Senior epidemiologist and former Director General Health Dr Rana Muhammad Safdar said the egg-based split-virion and subunit methods were all established vaccine manufacturing technologies capable of producing safe, high-quality and effective products. He said the real differences lay in quality control checks and post-marketing surveillance, which gave one manufacturer an edge over another.
In the present situation, Dr Safdar said, WHO prequalification was the key, as it involved strictly laid down standards. Once a vaccine met these criteria, he said, it could for all practical purposes be considered safe and effective, and used without concern or reservation.
Microbiologist and former NIH Executive Director Maj Gen Amer Ikram said he had found no credible scientific evidence showing that licensed, standard-dose Chinese inactivated vaccines gave less protection than equivalent Western standard-dose vaccines. Available head-to-head data, he said, pointed to comparable immunogenicity and safety.
He said the real differences lay in how much regulatory assurance and independent evidence stood behind each product, which varied by manufacturer rather than by country.
Maj Gen Ikram explained that Sinovac’s Anflu, Hualan’s vaccine and Sanofi’s Vaxigrip were all egg-grown, inactivated split-virion vaccines, while Abbott’s Influvac was an inactivated surface-antigen, or subunit, vaccine. Anflu contains 15 micrograms of haemagglutinin per strain in a 0.5 ml dose, he said, the same antigen content as Western standard-dose products.
All of them, he added, use WHO-recommended strains and are potency-tested in the same way. Split and subunit vaccines differ slightly in reactogenicity, meaning the likelihood of side effects such as soreness or mild fever, but their protection is generally considered equivalent.
The experts’ comments relate to licensed, standard-dose vaccines from established manufacturers. They do not apply to unlicensed or counterfeit products, which the drug authorities have warned are circulating in the market. The Punjab drug control office has urged the public to buy vaccines only from licensed pharmacies and to check the cold chain, batch number and manufacturer’s seal.
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