Does the ultra-fast transmission of the Delta variant make collective immunity impossible?

Collective immunity, also called collective immunity or collective immunity, is indirect protection against infectious disease obtained when a population becomes immune, either by having received a dose of a vaccine, or by having developed antibodies against the virus. Comprehensive COVID-19 vaccination aims to reduce severe cases and deaths, and achieve collective immunity to reduce the circulation of the coronavirus and control the pandemic.

Last year, mass vaccination campaigns around the world have just started and long before the strong circulation of new variants, it was calculated that 70% of the world’s population had to be vaccinated to achieve herd immunity. However, the new variants, described as worrying by the WHO, have led researchers to consider that a higher percentage of inoculated with two doses will be necessary for herd immunity.

In a survey, experts of The Economist Intelligence Unit (EIU), a business unit linked to the prestigious magazine The Economist which is dedicated to advising on economic, social and political issues to companies in the public and private sectors, analyzed the health strategies of governments in relation to mass vaccination, and the possibility of controlling the pandemic and thus achieving a sustained economic reactivation.

In the report, analysts determined that “the characteristics of the Delta variant mean that vaccines alone may not be sufficient to control it because it is much more transmissible than the parent virus. A patient infected with the line detected in India infects 5 to 9 other people, against 2 or 3 infections caused by the original strain. The conclusion of the study was decisive: “With the Delta variant, the overall collective immunity threshold seems unattainable.”

According to the findings of the report, “Vaccines, although they are a crucial first step in the fight against the pandemic because they offer protection against infections, serious illness and death, in fact they are not the magic solution that governments were waiting for because they do not prevent contagion, although, and this is not a minor data, they drastically reduce serious illnesses and hospitalizations. For this reason, scientists stressed that “it will force governments to rethink their strategy and consider living with COVID-19 to be the new normal.”

The economic cost of lack of immunity

The reactivation of trade and industry is one of the central themes of the document, for The Economist The economic and social cost of the unequal distribution of vaccines globally will lead to a sharp decline in GDP: “Countries that have not vaccinated 60% of their population by mid-2022 will experience losses totaling $ 2.3 trillion over the period 2022-2025. Emerging countries will bear around two-thirds of these losses, Asia being the most affected continent (with expected cumulative losses of $ 1.7 trillion “.

Regarding the health policies applied by the governments of various countries, the report stressed that “Australian or New Zealand policies are a lost economic opportunity”, Regarding the search for zero COVID-19 infections that these countries have carried out, “Which means that with a single contagion they carry out very strict confinements”.

The disparity in the inoculation rate of the population is a relevant factor in assessing the long-awaited economic recovery, the British magazine’s research unit detailed that “By the end of August, around 60% of the population in high-income countries had received at least one dose of the coronavirus vaccine”The study points out, adding that “on the contrary, vaccination campaigns are advancing at an icy pace in low-income economies. At the same time, only 1% of the poorest populations had received at least one dose of a vaccine ”.

The “hard setback” of the Delta variant

There are 4 variants classified as disturbing with a new world nomenclature defined by the WHO: Gamma (Line P.1, originally detected in Manaus); Alfa (line B.1.1.7, first reported in the UK); Beta (line B.1.351, registered in South Africa) and Delta (line B.1.617.2, which appeared in India).

Since April of this year, there has been an exponential increase in infections caused by the Delta variant around the world. As of July 2021, a global prevalence of Delta was observed in almost 90% of the samples sequenced worldwide. By the end of August, 163 countries had already detected cases of the viral lineage first identified in India in December 2020..

People infected with the Delta variant of the coronavirus run twice as likely to be hospitalized concerning people infected with the Alpha version, according to an in-depth study published last week in the journal Lancet Infectious Diseases. Taking into account factors that affect personal predisposition to develop severe symptoms of COVID-19, such as age, ethnicity and vaccination, scientists calculated that the risk of ending up in the hospital was multiplied. by 2.26 with the Delta variant.

With higher mortality, hospitalization rate and generalized transmission, Delta has suffered a serious setback in the idea of ​​”living with the virus”. “Eliminating the disease is not possible”, emphasizes The Economist, sending a message to optimize economic policies around the world, taking the UK as an example.

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