COVID-19 infections in the Chinese city of Wuhan, where the virus was first reported, may have been nearly 10 times higher than that reported. Despite the high number of COVID-19 cases, the immunity required to protect against another wave is still missing, said the serological survey conducted by the Chinese Centre for Disease Control and Prevention.
Of over 34,000 surveyed, only about 4.4 percent were found to have specific antibodies that can fight off the virus that causes COVID-19, as per the data released on December 27.
That ratio suggests that Wuhan, which houses about 11 million people, may have reported many as 5,00,000 cases of COVID-19, nearly 10 times more than the 50,000 confirmed cases reported by health authorities in mid-April, when the survey was conducted.
The China CDC survey also showed that the impact of COVID-19 was far less outside Wuhan, which was effectively isolated to contain the spread of the outbreak.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
Of the 12,000 surveyed in six other Chinese cities and provinces, including Beijing, Shanghai and Guangdong, only two people tested positive for the antibodies suggesting an extremely low prevalence of the virus across the rest of the country.
Several countries have criticised China for its initial handling of the outbreak, which has now spread around the world in a global pandemic in the year since the cases first emerged.
The United States and President Donald Trump has been one of the most vocal critics. As per several accounts, the cases and deaths reported by China were allegedly lower than the actual tally.
The coronavirus has killed at least 1.76 million people since the outbreak emerged in China in December 2019, according to an AFP tally on Monday based on official sources. At least 80 million cases have been registered.
The United States is the worst-affected country with 333,140 deaths, followed by Brazil with 191,139, India with 147,901 and Mexico with 122,426.Click here for Moneycontrol's full coverage of the COVID-19 outbreak