The United Nations health agency today reported “encouraging progress” in producing a vaccine against human bird flu, which in a worst case scenario could cause a deadly pandemic that could kill millions, but warned that the world still lacks the manufacturing capacity to meet potential global demand.
Experts meeting over the past two days at the UN World Health Organization (WHO) headquarters discussed latest developments, with 16 manufacturers from 10 countries developing prototype pandemic influenza vaccines against the H5N1 virus and five of them also focusing other bird flu strains such as H9N2, H5N2, and H5N3.
“For the first time, results presented at the meeting have convincingly demonstrated that vaccination with newly developed avian influenza vaccines can bring about a potentially protective immune response against strains of H5N1 virus found in a variety of geographical locations,” WHO said in a news release.
“Some of the vaccines work with low doses of antigen, which means that significantly more vaccine doses can be available in case of a pandemic,” it added.
But it warned that in spite of the encouraging progress, “the world still lacks the manufacturing capacity to meet potential global pandemic influenza vaccine demand as current capacity is estimated at less than 400 million doses per year of trivalent seasonal influenza vaccine.”
To counter this challenge, WHO last year launched the Global pandemic influenza action plan to increase vaccine supply, a $10-billion effort over a decade. One of its aims is to transfer technology to developing countries so they can set up their own influenza vaccine production units, providing them with the most sustainable and reliable response to the threat of pandemic influenza.
WHO is currently working with several vaccine producers, mainly in developing countries affected by H5N1 to facilitate in-country influenza vaccine production.
There have so far been 273 confirmed human cases worldwide, 167 of them fatal, the vast majority in South-East Asia. Indonesia has recorded the highest death toll – 63 out of 81 cases. UN health officials have been on constant alert to detect any mutation that could make the disease more easily transmissible in humans. Nearly all human cases so far have been traced to contact with infected birds.
The so-called Spanish flu pandemic of 1918-1920 is estimated to have killed from 20 million to 40 million people worldwide. More than 200 million birds have died from either the virus or preventive culling in the current outbreak.
At present, more then 40 clinical vaccine trials have been completed or are ongoing. Most have focused on healthy adults. Some companies, after completing safety analyses in adults, have initiated clinical trials in the elderly and in children. All vaccines were safe and well tolerated in all age groups tested.
More than 100 influenza vaccine experts – from academia, national and regional public health institutions, the pharmaceutical industry and regulatory bodies throughout the world – attended the Geneva meeting, the third that WHO has convened in just two years to review progress in developing vaccines against pandemic influenza viruses and to agree on future priority activities.