May 07, 2021 08:00:00

'Herd immunity cannot be achieved with the new corona vaccination,' experts are changing their mindset.

In Japan as well, inoculation of the new coronavirus vaccine has begun in each local government, and if a certain percentage of the population acquires immunity, even if an infected person appears, the infection to other people will decrease and the epidemic will

stop. Is expected to be achieved. However, the New York Times, an American daily newspaper that has begun vaccination a little earlier, released a column saying, 'In the United States, there is a growing view that it is difficult to achieve herd immunity by vaccination, and experts are changing their mindset.' doing.

Reaching'Herd Immunity' Is Unlikely in the US, Experts Now Believe --The New York Times
https://www.nytimes.com/2021/05/03/health/covid-herd-immunity-vaccine.html

At the time of writing, more than half of American adults were vaccinated at least once. It is estimated that the threshold for achieving herd immunity at an early stage is that about 60 to 70% of the population acquires immunity, and the realization of herd immunity is considered to be fairly close.

However, the New York Times said, 'Daily vaccination rates are declining, and there is widespread view among scientists and public health professionals that the herd immunity threshold cannot be met.' 'The new coronavirus is likely to spread and shrink in the United States over the next few years, becoming a much smaller and manageable threat than it is now,' he said.

Rustom Antia, an evolutionary biologist at Emory University , said, 'The new coronavirus will not go away, but we will do everything we can to ensure that the new coronavirus infection remains mild. I want to do it. '

The shift of experts from the idea of 'overcoming the new coronavirus with herd immunity' to the idea of 'retaining small and manageable infectious diseases' is also a new challenge for public health authorities. I will. Due to the fact that the goal of 'overcoming the new coronavirus with herd immunity' cannot be achieved, people skeptical of vaccination argue that 'why do we need to be vaccinated when we cannot achieve the goal?' It is more likely to increase your suspicion of the vaccine.

However, experts say, 'vaccination remains the key to turning the virus into a controllable threat.'

Anthony Fauci, an authority on human immunodeficiency virus (HIV) research and chief advisor to the COVID-19 response team of the Byden administration, said, 'Until the level of herd immunity is reached, everyone is confused by the new coronavirus. I thought we couldn't reduce the infection by any means, so we stopped using the word'herd immunity'in the classical sense. '

Fauci also said, 'I would like to say that the word'herd immunity'is forgotten. Proper vaccination of a sufficient number of people will reduce the number of new coronavirus infections. Let's do it. '

Herd immunity threshold estimates are based on the infectivity of the first virus strain that prevailed in the first half of 2020. However, at the time of writing the article, the existence of various mutant strains was also reported, and it is said that the subspecies confirmed in the United Kingdom are about 1.6 times more infectious. Therefore, recalculating the threshold revealed that at least 80% of the population must acquire immunity before they can acquire herd immunity, the New York Times reports.

Opinion polls show that about 30% of the American population is reluctant to vaccinate. This number is expected to decline little by little, but it is still quite a tough number to achieve herd immunity.

'Herd immunity is often talked about as a national goal, but disease transmissions occur locally, for example, across the United States,' said Mark Lipsich, an epidemiologist at Harvard's School of Public Health. Even if the vaccination rate is 90%, if it is 70% in some cities, then there is no herd immunity in that city. '

The map below shows the future vaccination rate (estimated) in the United States by region. The darker the color, the higher the vaccination rate is expected. Looking at this, there are many areas where the vaccination rate is estimated to be 80% or more in the east coast of the United States, around New York, the west coast of the United States, around California, and Minnesota, but in the northern and southeastern parts of the United States. Looking at it, there are many areas where the vaccination rate is below 60%.

If the herd immunity threshold cannot be met, the most important thing is to look at hospitalization and mortality after the pandemic is relaxed, the New York Times said. In other words, focus on vaccination of the 'most vulnerable people', such as the elderly and those at high risk of aggravation, so that the new coronavirus can be managed as a seasonal infection like influenza. The New York Times argues that it could fall into the same level.

'We believe that a complete eradication of the new coronavirus infection is not possible at this stage, but the local community carefully examines and tracks it,' said Barry Pradelsky, an economist at the French National Center for Scientific Research. If we can continue, health authorities may be able to identify the invasion of the virus and immediately stop the potential spread. '