New Delhi : Mass vaccination against the deadly H1N1 swine flu virus is likely to begin in India next week. The 1.5 million doses of vaccines imported by the government from Sanofi Pasteur have passed the safety test.

The French vaccine manufacturers submitted the results of their clinical bridge study -- conducted in Delhi and Pune on 100 adult subjects -- to the Drug Controller General of India on March 3. The trials were completed on February 21. The results were then checked thoroughly in Lyon before being submitted to DCGI.

DCGI Dr Surinder Singh told reporters, "The trials of the vaccine have proven its safety profile. By Friday, we will vet the results and give its clearance for use on humans in India. By next week, the vaccination should begin."

According to Union health ministry officials, 10 lakh doses of the vaccine will be sent to all Central government hospitals for administering on all frontline health workers and those at highest risk of getting infected. The rest will be given to the armed forces while some doses will be retained by the ministry.

The ministry was more concerned about the vaccine's safety. The vaccine's safety profile was checked twice -- first for seven days and then for 21 days. The trials took place in Kalavati Saran Hospital in Delhi and Bharatiya Vidyapith in Pune and the vaccines were found to be safe.

Dr Singh said, "We didn't want it to cause side-effects like the Guillain-Barri syndrome (GBS) -- a rare disease in which the body damages its own nerve cells, causing muscle weakness and sometimes paralysis. The company will, however, continue to check the vaccine's immunogenecity results, which will come in six weeks time."

Meanwhile, India's indigenous H1N1 vaccine is expected to be available by April 15 and could cost between Rs 80 and Rs 100.

Cadila Healthcare had on January 3 started human trials of India's live and inactivated indigenous H1N1 vaccine on 200 subjects. Three other Indian companies - Serum Institute (Pune), Bharat Biotech International (Hyderabad) and Panasia Biotec (New Delhi) - were also given clearance by DCGI to conduct human trials in January. These are expected to start soon.

While Serum will test the trials on around 350 people, Panacea has a subject size of over 1,100 and Bharat of 160. Dr Singh said, "If all goes well with the Indian vaccines and they prove safe and effective, they should be available commercially within April 15 and 30.

Experts, however, say no vaccine is 100% safe for everyone. People with allergies to eggs, for example, can't take flu vaccines because eggs are involved in the manufacturing process. H1N1 has spread to 210 countries. In India, it has infected over 29,710 people and killed 1,376 among them.