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KOMPAS.com – The World Health Organization (WHO) stated that at the end of 2020, the SARS-CoV-2 corona virus was the cause Covid-19 will not disappear, but will become endemic.
The meaning of endemic is that it continues to exist around humans, in the global population for several years and causes an outbreak in an area.
This is also believed by scientists working in the field.
But on the other hand, scientists also believe that the impact of Covid-19 on the world in terms of mortality, disease and the need for isolation will decrease over time.
Also read: WHO Warns, The Covid-19 Pandemic Is Most Likely To Be Endemic
This can happen because later many people acquire immunity because they are infected with Covid-19 or from vaccination.
Reported BMJ, February 18, 2021, the prediction comes from a survey conducted in January by the journal Nature of more than 100 immunologists, infectious disease researchers, and virologists working with SARS-CoV-2.
The data shows that nearly 90 percent of respondents said they expected the corona virus to be endemic. And a third of respondents think that it is possible to eliminate SARS-CoV-2 from several regions of the world.
“Although there will be a risk of a Covid-19 outbreak in these areas, this can be contained by herd immunity. That is, if most people have been vaccinated,” said Christopher Dye, an epidemiologist at the University of Oxford, UK.
“I think Covid will disappear from some countries. But there is a risk of this disease being sustainable and possibly seasonal, especially in places where vaccine coverage and public health measures are not good enough,” he added in an interview with Nature.
Covid-19 is currently classified as a pandemic phase because infections continue to increase worldwide and many people are still vulnerable.
In the endemic phase, the number of infections remains relatively constant over the years, with occasional relapses.
Antibodies and reinfection
“Over time, Covid-19 could become a disease that is first seen in early childhood, by causing mild or no infection (causing symptoms),” said Jennie Lavine, an infectious disease researcher at Emory University in Atlanta, USA, said to Nature.
While those defenses will diminish rapidly and are not sufficient to completely block reinfection, they can be sufficient to protect adults with severe symptoms.
Scientists think this scenario may be because it matches four existing endemic coronaviruses – OC43, 229E, NL63, and HKU1 – but it’s not certain what is known.
A large study has shown that neutralizing antibody levels start to decline after about 6-8 months after becoming infected with SARS-CoV-2.
If new infections emerge, memory B cells can produce antibodies and T cells that can eliminate virus-infected cells, but it is not yet certain whether these immune memories block reinfection of the virus.
“It can take years or even decades to reach a state where a sufficiently large population has sufficient immunity,” Lavine added.
“Allowing the virus to spread uncontrollably would be the fastest way to get to that point, but it would result in millions of deaths, so the most suitable route is through vaccination,” he said.
Modeling results about Covid-19
A model developed by Alexandra Hogan at Imperial College London and her colleagues suggests that if you want to achieve herd immunity, at least 55 percent of a region’s population must receive a vaccine that is 90 percent effective. However, it still has to implement protocols of maintaining distance, wearing masks, and many people working from home.
Meanwhile, if you want the distance keeping protocol to be eliminated, the same vaccine must cover 67 percent of the population.
If the effectiveness of the vaccine used is less than 90 percent in preventing transmission of the virus, or if there is a new virus variant, the percentage of vaccination coverage must be even greater.
The results of preprinted or preprinted studies from laboratory research show that neutralizing antibodies in the blood of people who have contracted Covid-19 are less able to recognize the variant of the virus first identified in South Africa (called 501Y.V2) than the variant circulating earlier in the pandemic.
Also read: WHO Could have lifted the status of the pandemic sooner in this country, provided that
More than 70 percent of researchers surveyed by Nature believe that the ability to adapt and evade immune defenses will promote sustainable circulation of SARS-CoV-2.
As a result, an updated vaccine may need to be developed and administered, perhaps annually like the flu vaccine.
The future impact of SARS-CoV-2 will also depend on how well it thrives in wild animal populations.
Some of the diseases that have been controlled, including yellow fever, Ebola, and the chikungunya virus, survive because of animal shelters.
SARS-CoV-2 probably originated in bats and can easily infect many animals, including cats, rabbits and hamsters, and is highly contagious in mink.
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