Has Delhi really passed its coronavirus peak?

As per recent health department bulletins the number of COVID-19 cases had dropped quite a bit over the past week. While the administrations are at loggerheads over how to control the pandemic, the drop in the number of cases in Delhi on Monday gave a glimmer of hope to Indians.
With the third-highest number of coronavirus positive cases in the world after the United States and Brazil, India has a recovery rate of 84%.

On Monday, when reported cases were below 1000, AIIMS Director Randeep Guleria said, “My feeling is that certain areas have hit their peak. Delhi seems to have done so because the cases have declined significantly. But certain areas are yet to reach their peak. Cases are increasing in certain states. They will reach the peak later,” reported NDTV.

But the very next day reported cases reached 1,349, and as of Thursday, the number in Delhi rose to 1,27,364 with 1,041 fresh cases.

Credit: Twitter

1 in 4 exposed to virus

A study, conducted by National Center for Disease Control in collaboration with the Delhi government, with a total of 21,387 blood samples, from June 27 to July 10 found 23.48% to have Covid-19 antibodies. This indicates that about 1 in every 4 persons had had past exposure to the coronavirus.

“The government has decided to conduct serosurvey every month to understand the spread of the virus in the national capital,” said Dr Satyendar Jain. Sero surveys estimate the proportion of the population exposed to infection. (Rapid antigen tests are not used for serosurveys)

This also is an eye-opener as the study indicates that actual infections in the city are much more than the number of confirmed cases shows. As per a press release from the health ministry, a large number of infected people are still asymptomatic, which is probably how the infection is spreading faster. Delhi is not out of danger yet.

Credit: Facebook

People without symptoms are oblivious to the fact that they are carriers of a deadly virus and hence not getting tested. They, in turn, unknowingly infecting others who come in contact with them.

The test that is used to diagnose and treat Covid-19 worldwide is RT-PCR (reverse-polymerase chain reaction), which involves taking swabs from the nasal and oral tracts to detect SARS-CoV-2. Another method in RT-PCR is bronchoalveolar lavage (BAL) method which claims to have better detection abilities. TrueNat also involving nasal and oral swab tests works on the same principle as RT-PCR.

Rapid antigen tests, that looks for antibodies in the blood by taking a sample and putting it in a testing template, on the other hand, are not fully reliable. If a person tests positive through a rapid test, he/she has to undergo a confirmatory RT-PCR test before treatment.

When the Delhi government claimed to have increased testing across the state, it was the rapid antigen test that was increased. According to the Indian Council of Medical Research, the sensitivity of the rapid tests was found, in two separate studies, to be 50.6% and 84%, reports TheWire.

A significant drop can be seen in positive cases in July as compared to June, but with the uncertain results of the rapid tests, it remains a question whether the apparent drop is genuine or just an illusion due to the wide use of rapid tests instead of RT-PCR tests. Given the disparity between the results of the 2 studies sited by ICMR it pretty much can be concluded that the results form the rapid antigen tests are not solely reliable which is why ICMR has not yet approved the use of rapid tests in diagnosis. The sudden drop in positive cases can thus be constituted to the increase of this not-so-reliable test by the Delhi government lately.

What now?

A letter published in the Clinical Infectious Diseases journal from more than 200 scientists a couple of weeks ago said that “beyond any reasonable doubt viruses are released during exhalation, talking and coughing in microdroplets small enough to remain aloft in the air.” After the letter called on the World Health Organization to address the airborne spread of the coronavirus, WHO eventually acknowledged that spread of the virus “particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons cannot be ruled out.” The agency also said, “the extent of truly asymptomatic infection in the community remains unknown.”

World Health Organization flag | Credit: Commons

With this relatively new information the whole concept of contracting the disease changes, and makes us question if the precautions that we have been taking so far are helpful.

Also, with no other ways to prevent oneself from getting infected, abiding by the guideline set by the government, and maintaining a healthy diet to enhance the immune system are what we should focus on now to flatten the curve and beat the coronavirus.

Since over 75% people are still vulnerable to the virus not having developed antibodies, people must continue to maintain social distance, wear masks in public places, and wash their hands frequently with soap or use hand sanitizers. No matter how frustrating it seems we must still not venture out to public places until absolutely necessary.

Will achieving herd immunity end the virus?

The serosurveys indicate whether the people are moving towards herd immunity. Herd effect is a form of indirect protection from an infectious disease when a large percentage of a population has become immune to the infection, either through previous infections, or vaccination. This eventually shields those who are not immune, as others around them are already immune to the diseases and cannot transmit it further. Gradually, the chain of infection is disrupted, and the spread of the disease either stops or slows down considerably.

Credit: iStock

Herd immunity protects at-risk populations like babies and older adults whose immune systems are weak and can’t get resistance on their own.

An article published by The Guadian recently highlighted a UK research saying immunity to Covid-19 is shortlived. Prof Stuart Neil, a co-author on the study was quoted, “One thing we know about these coronaviruses is that people can get reinfected fairly often. What that must mean is that the protective immunity people generate doesn’t last very long. It looks like Sars-Cov-2, the virus that causes Covid-19, might be falling into that pattern as well.”

This does not give very high hopes to end the virus any time soon, rather gives an impression that it might become a normal aspect of our lives herewith.

Even if the chances of eradicating the virus altogether seems bleak, herd immunity, no matter how brief it is, will ensure control on the rapidly increasing cases. Even if one contracts the virus for a second time, chances of getting affected as badly as before will be considerably less with immune memory retained by their bodies.

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