Every second person infected with coronavirus in Delhi

[GS Zhou]

Every second person infected with coronavirus in Delhi, signs of herd immunity in fifth serosurvey

According to Delhi government sources, the preliminary trend of Delhi's fifth serosurvey has revealed that around 50% of the population i.e. 1 crore people have been cured after being infected with the coronavirus.

Pankaj Jain
New Delhi
January 25, 2021UPDATED: January 25, 2021 19:30 IST

While on the one hand vaccination has started against coronavirus in full steam in India, the results of the fifth serological survey in Delhi have brought both relief and surprise. According to the latest serosurvey, 1 in 2 people in Delhi were likely infected by Covid-19 and then got cured.

Multiple rounds of serosurveys have been conducted by the Delhi government to assess the spread of coronavirus infection in the national capital. The fifth and the largest serosurvey of Delhi was conducted in January 2021. In a serosurvey, samples of blood are collected from the person's body and then medical team tests whether antibodies have been formed against coronavirus in the blood or not.

According to Delhi government sources, the preliminary trend of Delhi's fifth serosurvey has revealed that 60 per cent of people in one particular district in Delhi have been found to have Covid-19 antibodies. This means that they were unknowingly infected with coronavirus and got cured later. Whereas in other districts, more than 50 per cent of people were found to have antibodies and had therefore come in contact with coronavirus.

Delhi has a population of more than 2 crores and the fifth serosurvey indicates that around 1 crore population has been cured after being infected with the coronavirus.

The outcome of the fifth round of seroprevalence survey in the national capital has indicated that Delhi population could be heading towards attaining herd immunity against coronavirus infection.

Dr Arun Gupta, President of Delhi Medical Council has explained herd immunity in 3 parts:

1. It is very important to first understand what is herd immunity. If a large population has an antibody against a disease, then it stops the spread of that disease and the rest of the population can be saved from infection.

2. Herd immunity can occur in two ways -- one by the natural spread of infection or by vaccination. As scientists and doctors, we always wish that herd immunity comes from vaccination.

3. If antibodies against infection are found in 60 per cent of the population, then, in this case, we can assume that the rest of the population which does not have antibodies can also be protected from the infection.

Dr Gupta further said that the result of serosurvey in Delhi is very good. "This is why the outbreak of coronavirus is decreasing in Delhi. Also, the way the vaccination drive is going on, Delhi will soon get over Covid-19," he said.

The fifth serosurvey of Delhi is the largest serosurvey to date. A total of 28,000 people were sampled in this survey. 100 samples were taken from every municipal ward of Delhi. The survey has been conducted from January 10 to January 23. The first serosurvey in Delhi was conducted in June-July in which antibodies were found in 23.4 per cent people. Antibodies were found in 29.1 per cent of people in August. This was followed by antibodies in 25.1 per cent in September and 25.5 per cent in October.

Delhi recorded 185 fresh Covid-19 cases on Sunday, the third time the daily incidence count stood below the 200-mark in January, even as the positivity was recorded at 0.30 per cent.

Health Minister Satyendar Jain recently said the pandemic situation in the city is now under control.

The infection tally in the city stood at over 6.33 lakh and the death toll mounted to 10,808 with nine new fatalities on Sunday.

Every second person infected with coronavirus in Delhi, signs of herd immunity in fifth serosurvey

According to Delhi government sources, the preliminary trend of Delhi's fifth serosurvey has revealed that around 50% of the population i.e. 1 crore people have been cured after being infected with the coronavirus.

www.indiatoday.in

 

[xuxu1457]

I think the good news is that India no longer needs the vaccine, it has completed herd immunity.
60% of the people have antibodies can be herd immunity

 

[GS Zhou]

I think the good news is that India no longer needs the vaccine, it has completed herd immunity.
60% of the people have antibodies can be herd immunity

A very recent research paper from Science. The paper analyzed the covid spread situation in Manaus, a big city in Brazil, where even with an estimated 76% of the population being infected, herd immunity was not achieved.

Science | AAAS

science.sciencemag.org

Herd immunity by infection is not an option

1. Devi Sridhar,
2. Deepti Gurdasani

See all authors and affiliations
Science 15 Jan 2021:
Vol. 371, Issue 6526, pp. 230-231
DOI: 10.1126/science.abf7921

• Article
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Gravediggers bury a deceased COVID-19 patient at the Parque Taruma cemetery, Manaus, Brazil, where the disease has caused a huge number of deaths.
PHOTO: BRUNO KELLY/REUTERS
Herd immunity is expected to arise when a virus cannot spread readily, because it encounters a population that has a level of immunity that reduces the number of individuals susceptible to infection. On page 288 of this issue, Buss et al. (1) describe the extent of the largely uncontrolled severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Manaus, the capital of Amazonas state in Brazil. Their data show the impact on mortality rates of a largely unmitigated outbreak where even with an estimated 76% of the population being infected, herd immunity was not achieved. Manaus provides a cautionary example of unmitigated spread across a population, showing that herd immunity is likely not achieved even at high levels of infection and that it comes with unacceptably high costs.
Buss et al. used data on the occurrence of SARS-CoV-2–specific antibodies (seroprevalence) in blood donors, adjusted for waning antibody responses over time, to calculate an estimated attack rate for COVID-19 of 66% in June, rising to 76% in October, in Manaus. The attack rate is the proportion of at-risk people who develop infection after exposure in a period of time. This attack rate resulted in a factor of 4.5 excess mortality in 2020 relative to previous years. The infection fatality rate was estimated to be between 0.17% and 0.28%, consistent with the population being predominantly young and at reduced risk of death from COVID-19. Manaus recorded 2642 [1193/million inhabitants (mil)] confirmed deaths from COVID-19 and 3789 (1710/mil) deaths from severe acute respiratory syndrome likely to have been caused by SARS-CoV-2 infection. These figures are starkly different from the fatality rates during the same period (until 1 October) in the United Kingdom (620/mil), France (490/mil), and the United States (625/mil), and orders of magnitude higher than in Australia (36/mil), Taiwan (0.3/mil), and New Zealand (5/mil). Despite such a high proportion of the population being infected, transmission in Manaus has continued, even in the presence of nonpharmaceutical interventions (NPIs), with the effective reproduction rate (R) near 1.
These data have numerous implications. In particular, the herd immunity threshold (HIT), the proportion of the population that needs to be immune to reduce the number of susceptible individuals sufficiently to reverse epidemic growth, is likely to be high for SARS-CoV-2. If the basic reproduction number (R0)—that is, the average number of secondary infections resulting from an index case in a fully susceptible population—is 2.5 to 3, as estimated within Manaus, the expected attack rate would be 89 to 94% and the HIT is expected to be 60 to 70% for a homogeneous population (2). Although the epidemic was largely unmitigated in Manaus at the outset, the subsequent introduction of behavioral change (such as social distancing) and NPIs (such as masks), together with nonhomogeneous population mixing, may explain the lower than expected attack rate. However, even with an estimated 76% of the population being infected, it appears the HIT was not reached. It is unclear whether this is due to waning immunity after infection, to a higher HIT than previously anticipated, or possibly a lower attack rate than estimated. Accruing data on reinfection with SARS-CoV-2 suggests that primary infection may not consistently confer long-term immunity to all infected, although the frequency of reinfection and the correlates of an effective immune response remain poorly understood. If immunity wanes over time, exposed individuals may revert to becoming susceptible, providing a new susceptible population that may then contribute to transmission.
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These findings also suggest that the majority of people who are unexposed are susceptible to this virus. Although some have suggested that there may be a degree of preexisting cross-reactive T cell and humoral (antibody-related) immunity against SARS-CoV-2 (3, 4) and that a lower proportion of infection of only 10 to 40% of the population could achieve herd immunity (5), the study of Buss et al. shows that there is no meaningful level of any such immunity.
Additionally, given that seroprevalence is under 20% in most countries (6), these data suggest that without strict control measures, the epidemic would continue to accelerate for many months ahead, with an unacceptably high cost. The deaths that would accrue in pursuit of naturally acquired herd immunity would be catastrophic. Manaus has a particularly young population. In populations with a higher proportion of older people, the overall infection fatality rates would be higher, between 0.46% and 0.72% as seen in São Paulo (1). Applying age-specific infection fatality rates estimated from the Manaus data, a 76% attack rate would mean 350,000, 386,000, and 1.58 million deaths in the United Kingdom, France, and the United States, respectively.
Buss et al. reported similar seroprevalence estimates across the age groups studied, which suggests that spread appears to have occurred relatively uniformly across the population and was not limited to specific subsets of people who may have been more exposed. This is consistent with other global evidence suggesting that it is practically impossible to “shield” the vulnerable or to carry out “focused protection” given the difficulty of identifying and separating the healthy from the vulnerable (7). Inevitably, with unmitigated transmission, infection will spread to vulnerable populations, with attendant costs (8).
Even in a younger population, SARS-CoV-2 is harmful and deadly. The growing evidence of long COVID and its long-lasting multisystem effects indicates that there may be substantial morbidity after infection (9, 10). Although the risk of long COVID seems to increase with age, recent reports of multisystem disease and long COVID among children suggest that the risk in younger age groups cannot be overlooked (11). This highlights the risks associated with exposing large swaths of the population to a virus that is still not fully understood. Strategies for suppression of COVID-19 should not focus only on older people or those with comorbidities, but rather on the entire population, given the substantial impact of unmitigated infection on the health of all groups and the economic impacts of poor health among these groups on society as a whole.
There remain major unknowns about how long immunity to SARS-CoV-2 lasts and the risk of reinfection (12). Seasonal coronaviruses, which cause common colds, are known to induce short immunity, and reinfections occur commonly within 12 months of infection (13), although immunity to SARS-CoV and MERS-CoV, which cause more severe disease, can last several years (14). T cell immunity might be longer-lasting, but it is unclear whether this would fade within 1 to 2 years (3). If immunity does fade, this would mean that recurrent epidemic cycles are likely, especially if new strains that can escape immune detection emerge.
What the findings of Buss et al. definitively show is that pursuing herd immunity through naturally acquired infection is not a strategy that can be considered. Achieving herd immunity through infection will be very costly in terms of mortality and morbidity, with little guarantee of success. Although the duration and effectiveness of immunity in reducing transmission with vaccination is unclear, experience across several infectious diseases suggests that immunity can be boosted safely through vaccination, if required. Even a mitigation strategy whereby the virus is allowed to spread through the population with the objective of keeping admissions just below health care capacity, as is done for influenza virus, is clearly misguided for SARS-CoV-2. Like SARS-CoV and MERS-CoV, this virus is optimally addressed with an aggressive suppression strategy (15). Governments need to focus on more precise NPIs, robust test/trace/isolate systems, border control measures, mass testing, better treatments, and development and delivery of vaccines (15). This is the most sustainable path for countries out of this pandemic.

 

[Capt. Karnage]

Scare campaign to sell useless and potentially dangerous covid vaccines. It's just a normal flu people.

 

[ToddBing]

At least one thing is confirmed:"NO TEST,NO CASES".
So what's the real number that Indian govt has covered up???

 

[Feng Leng]

High antibody rate in Delhi means India could become coronavirus 'base camp' once borders reopen - Global Times

www.globaltimes.cn

While Indian media hailed the high rate of antibodies against novel coronavirus in the New Delhi population, seeing it as a step closer to achieving "herd immunity," Chinese experts expressed shock at the epidemic situation in the country, and warned that India could become a global "base camp" for the virus when borders reopen as the country is turning a blind eye to detecting and treating coronavirus patients.

The latest positive rate from a serological survey in Delhi was about 60 percent, indicating that at least one in two people in the capital of India had been infected with the virus, according to a report by India Today on Monday.

The data demonstrated that at least half of the city's 20 million population had been infected with the novel coronavirus, but official data released by its health authorities only recorded about 630,000 confirmed cases in the city, and just over 10 million total infections in the entire country.

Behind the high rate of positive antibodies is the suffering of millions of Indians who have not been detected due to insufficient domestic anti-epidemic policies. If India continues its laissez-faire approach, more Indians will get infected, a Beijing-based immunologist, who requested anonymity, told the Global Times on Tuesday.

"When borders between countries reopen, these untested but infected could make the country a base camp for novel coronavirus and spread the virus to the rest of the world, "the expert warned.

Echoing the anonymous expert, Tao Lina, a Shanghai-based expert on vaccines and immunology, also told the Global Times on Tuesday that the investigation results show the real infection situation in India and how bad the epidemic prevention and control measures are in the country.

"It possibly means the percentage of asymptomatic patients is extremely high in the city, and India has failed to detect and treat those infected people," Tao said.

Moreover, such antibodies could be temporary and may not guarantee that India itself is safe from future epidemics, due to its slow speed in rolling out its vaccination program and threats posed by mutated viral variants which have stronger virulence, experts said.

 

[Feng Leng]

India is the jewel in the UK-mutation corona!

 

[52051]

Just like flu and cold, COVID-19 wont be a deadly disease in hot and humid locations, not just India, most countries in South East Asia don't have much problem in deal with that virus.

That's why I suspect a theory that this coronavirus could arise in South Asia/South East Asia for a long time but nobody noticed that, before it reach the northern states through food and other import.

That's why the virus first arose in Wuhan's wet market where lots of imported meat/sea foods are sold.