Interpreter: Viral pandemic reaches herd immunity

Sidney (Reuters)-The new coronavirus pandemic hopes to bring “collective immunity” to the consciousness of the public, helping this phenomenon slow or stop its onset.

Herd immunity causes most of the community to develop some immunity to the virus, thereby reducing person-to-person transmission. As a result, the entire community is protected, not just those with immunity.

(Click here for Reuters graphics on how the vaccine slows the spread of the virus here(EXPLAINER)/ygdvzmqqgpw/index.html)

Natural infection and vaccination

There are two routes to herd immunity: natural infection or vaccination.

Natural infection means that many people have become ill and have recovered. However, with the new coronavirus, the degree of protection from natural infection is unknown. In addition, more people die while waiting for the herd to immunize than if the vaccine were produced.

“The risks are unacceptable,” said Katherine Bennett, epidemiology chairman of the School of Health at Deakin University in Melbourne. “If we know very little about the long-term effects, we can’t afford to infect people to reach herd immunity.”

Vaccination can provide widespread immunity faster and more reliably.

There is no vaccine against COVID-19-a disease caused by the new coronavirus-but trials at various stages are ongoing worldwide. It usually takes years for a vaccine to be identified, tested, manufactured and distributed for public use. Vaccine manufacturers want to dramatically compress the COVID-19 timeline with faster testing and large-scale manufacturing before the product is successful.

Experts believe that, if no other measures are taken, herd immunity can develop when 50-70% of the population becomes vaccinated. The exact level depends on the effectiveness of the vaccine. According to experts, the effective rate of vaccine is at most 70%.

Balance of vaccine distribution

How the vaccine is distributed affects efficacy. If shared unevenly, such as when wealthy people have more access than those in poor places, a secure cluster is created, but a large area of ​​vulnerable people remains ..

In the early stages of distribution, health care workers and others at the forefront, or those considered the most vulnerable-a process known as targeted vaccination may be given higher priority .. As a result, there is a risk of missing people who may be considered “super spreaders”, such as public transport workers.

Joel Miller, a senior instructor in applied mathematics at the Latrobe University in Melbourne, uses mathematical models to formulate policies by governments and non-profit organizations to deal with infectious diseases.

Movement limitation

The movement of people also affects the spread of the virus.

At low vaccination levels, the ultimate number of people infected will be the same in the widely mixed travel group and the relatively static group. However, because of the much slower spread of the static population, governments around the world impose lockdown measures.

Even if a high proportion of the population is vaccinated, if people refrain from traveling, the number of infections can drop even further.

While waiting

The new coronavirus spreads primarily through droplets that are released when a person coughs, sneezes, or speaks.

Until a vaccine is developed, masks, physical distances, and hand hygiene can reduce infections and boost herd immunity.

Epidemiologists largely agree that the combined approach is important given that the early vaccines on the market are likely not 100% effective.

“It’s about adding layers,” said Bennett of Deakin University. “It gives us further protection from the spread of the community. The situation is much better where the combination of measures is used.”