Manas Dasgupta
NEW DELHI, Nov 19: Can you feel safe if you test negative? If some of the “experts” are to be believed, at no stage, positive or negative, you can feel safe and mix with others. If their advice is to be taken to make the world “Corona-free,” every individual should live in isolation for unending “batches of 14 days period.”
If some “experts” scoff at people’s gatherings for any celebrations, be it Durga Puja by Bengalis, Diwali all over India, Chhath Puja in north India or Thanksgiving leading to Christmas in the Christian world, some other “experts” maintain that even Covid-19 vaccines as and when come out in the market, would not be a solution to the problem. “No vaccine is cent per cent safe nor would be able to give any guarantee of safety, maintaining social distancing and taking other precautionary measures will be must even after vaccines hit the market,” some senior scientists connected with World Health Orgnisation (WHO) claimed.
Many scientists do not agree that a person with a negative test result will not spread Covid-19. They say there is no guarantee that a negative report will be safe. Rather, they add, it creates “false hope.” Therefore, they say it is advisable that a person who has been exposed to Sars-Cov-2, the virus which causes the coronavirus disease, should still follow the mandated guidelines as a precautionary measure.
“You should not rely on test results alone to safely socialise in person. A test can only tell you if you are positive at a given moment in time, and can also fail to detect cases if you are infected but not yet shedding substantial virus,” Dr Angela Rasmussen, a virologist affiliated with Georgetown Center for Global Health Science and Security, was quoted as saying by the media.
The scientists, however, are silent as how an asymptomatic person would know when he had been “exposed” to the virus and when should his or her 14 days quarantine period begin. By their own reckoning, every individual, positive or negative, should stay indoors in isolation for batches or 14-day period endlessly because of the uncertainty when they have been “exposed” to the virus.
Giving the reasons for such perpetual isolation, the scientists said, “A person who has been exposed to the virus can take days to actually show symptoms of the viral disease. Experts say a test result could fail to detect the presence of the virus in the body if the exposed person is tested shortly after getting infected. The virus needs to reproduce enough copies of itself for it to be detected in the Covid-19 tests. The incubation period for Covid-19 is up to 14 days. And before that, a person can test negative and have no symptoms at all.
“There is also a possibility that a person may contract the virus after getting the test done. Hence it is advisable for the exposed person to stay under quarantine for at least a week after exposure to the virus,” the scientists said.
Giving the efficacy of various tests, the scientists said Antigen tests were rapid tests which give results within an hour or so. They are performed with nasal swabs and look for the presence of a specific protein on the surface of the virus. As the person gets results within hours, they are widely being used to test asymptomatic persons. However, there is a high chance of getting a false negative report with a rapid antigen test.
Molecular tests are the RT-PCR tests which look for virus’ genetic material in the body. This test is performed with nasal swabs or throat swabs or both. RT-PCR tests are more credible but then it can take days to give results.
The Director General of the WHO Tedros Adhanom Ghebreyesus himself did not feel the necessity of any tests and returned after self-isolation. The WHO chief said he did not feel the need to get tested as he followed all protocols. “‘I was OK, no symptoms. It’s day 17 now, and I followed the protocols. Because of no symptoms and full follow up of the protocol, I did not see the need for testing, he said during a briefing session. ‘I can assure you that I’m OK and actually very, very busy. The most important thing is following the protocol,’ Tedros added. The head of the World Health Organization had gone into self-quarantine after someone he had been in contact with tested positive for Covid-19. He had made the announcement on Twitter but stressed that he had no symptoms.”
Even as various COVID vaccine candidates are claiming anything between 90% to 96.4% efficacy amidst a world-wide rush to prove itself the “first in the market,” the WHO had on Wednesday cautioned the people that they should not feel “safe” and take life easy on vaccines hitting the market or even after actually taking a vaccine dose pointing out that no vaccine candidate had given total guarantee of safety nor such an assurance was possible unless the trial continued for at least a decade or so. Mike Ryan, the World Health Organization’s top emergency expert, said it would be at least 4-6 months before significant levels of vaccination were taking place around the world.
However, amidst the gloom, the good news is the third-phase trial of Bharat Biotech’s Covid-19 vaccine candidate, Covaxin will begin from Friday. Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences (PGIMS), Rohtak, hopes to get 1,000 healthy volunteers for the third-phase, informed Vice-Chancellor OP Kalra. “We are hoping to get 1,000 healthy volunteers by Thursday. Of them, 200 volunteers will be administered the Covaxin initially so that we get to know about their antibody response. There are three centers in the country where antibody response is studied. If the response is good in 600 volunteers, then ICMR will take permission for market authentication so that mass production can be done,” Kalra said. He further said, “Two doses will be injected to each volunteer. The second dose will be administered after 28 days of giving the first dose.”
Pfizer Inc and BioNTech could secure emergency U.S. and European authorization for their COVID-19 vaccine next month after final trial results showed it had a 95% success rate and no serious side effects, the manufacturers said.
The vaccine’s efficacy was found to be consistent across different ages and ethnicities – a promising sign given the disease has disproportionately hurt the elderly and certain groups including Black people.
The U.S. Food and Drug Administration could grant emergency-use by the middle of December, BioNTech Chief Executive Ugur Sahin told the media. Conditional approval in the European Union could be secured in the second half of December, he added.
“If all goes well I could imagine that we gain approval in the second half of December and start deliveries before Christmas, but really only if all goes positively,” he said.
The experts said the success rate of the vaccine developed by the U.S. drug-maker and German partner BioNTech was far higher than what regulators had said would have been acceptable. Experts said it was a significant achievement in the race to end the pandemic.
“A first in the history of mankind: less than a year from the sequence of the virus to the large-scale clinical trial of a vaccine, moreover based on a whole new technique,” said Enrico Bucci, a biologist at Temple University in Philadelphia. “Today is a special day.”
Another vaccine manufacturer, Moderna Inc on Monday released preliminary data for its vaccine showing 94.5% effectiveness. “We now have two safe and highly effective vaccines that could be authorized by the Food and Drug Administration and ready to distribute within weeks,” U.S. Health and Human Services Secretary Alex Azar said.
The Moderna vaccine is likely to be authorized within seven to 10 days of Pfizer receiving its EUA and the states were ready to begin distribution within 24 hours, the US officials said.
The better-than-expected results from the two vaccines, both developed with new messenger RNA (mRNA) technology, have raised hopes for an end to the pandemic. The Pfizer-BioNTech shot was found to have 94% efficacy in people over age 65, a particularly high-risk group.
“This is the evidence we needed to ensure that the most vulnerable people are protected,” said Andrew Hill, senior visiting research fellow at the University of Liverpool’s department of pharmacology.
