Written By: Longjam Dineshwori | Updated : July 21, 2020 2:02 PM IST
The swine flu pandemic that was first described in North America in April 2009 caused about 284,000 deaths worldwide. © Shutterstock
Scientists around the world are in a race against time to develop a vaccine to protect people against the novel coronavirus. More than 150 vaccine candidates are being developed across the globe, with some countries claiming to launch a potential shot with this year. Russia is ready to start phase 3 trials of one of its promising COVID-19 vaccines from August 3. But the country's Health Minister Mikhail Murashko has indicated that the vaccine could be made available to the general public before it clears the final trial. Oxford University's highly-touted COVID-19 vaccine, called AZD1222, is already in large-scale Phase III human trials and it is expected to be released in September. India has also started clinical trials of its first indigenous COVID-19 vaccine 'Covaxin' across the country. The vaccine developed by Bharat Biotech is planned for launch in August. It's been more than seven months now since the coronavirus outbreak started in China. Why it is taking so long to develop a vaccine against the virus? In 2009, when swine flu hit the world, scientists were able to come up with a vaccine in a little over five months.
The swine flu pandemic that was first described in North America in April 2009 caused about 284,000 deaths worldwide. The influenza virus is believed to have transmitted from pigs to humans. When the virus swept the world, scientists were in a similar rush like today to develop a vaccine. Work on a vaccine began in late April 2009 and the first doses of the shot were given to people on October 5 in the U.S. By November 2009, the swine flu vaccine was available in over 16 countries. The World Health Organization declared an end to the pandemic in August 2010.
The 2009 swine flu was the second pandemic involving the H1N1 influenza virus, the first being the 1918 1920 Spanish flu pandemic.
While the 2009 virus was a new strain of the flu, scientists knew early on what is needed to trigger the immune response. Plus there was already a flu vaccine that could be adjusted, as needed.
But this is not the case with COVID-19, which is caused by a new strain of the coronavirus. There were already known coronavirus strains, but they never resulted in a vaccine. Scientists still don't know much about the novel coronavirus. They are not very clear about the protective immune response against the disease. Currently, there is no evidence to prove that people who have recovered from COVID-19 are protected. Some researchers have suggested that antibodies can give immunity to patients only for a few months.
The 2009 flu pandemic vaccines either contained inactivated (killed) influenza virus or weakened live virus that could not cause influenza. For the production of the vaccines, the virus was grown in chicken eggs.
A coronavirus vaccine developed by the University of Oxford has shown positive results in initial trials. The researchers have found antibodies and T-cells that can fight coronavirus in volunteers who were given the vaccine.
The vaccine also called ChAdOx1 nCoV-19 is made from a genetically engineered virus that causes the common cold in chimpanzees. It has been modified so that it cannot cause infections in people and also make it "look" more like coronavirus. As the vaccine resembles the coronavirus, the immune system can learn how to attack it.
The vaccine is in the final phase of clinical trials and it is likely to be proven effective before the end of the year. However, widespread vaccination may be possible only next year even if everything goes well.
