Reach herd immunity with a viral pandemic

Sydney — The new coronavirus pandemic is expected to bring “collective immunity” to the consciousness of the masses, helping to delay or end the outbreak.

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.

Natural infection vs 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 cannot 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 immunized by vaccination. The exact level depends on the effectiveness of the vaccine. According to experts, the effective rate of the vaccine is at most 70%.

Balance vaccine distribution

How the vaccine is distributed affects its effectiveness. If they are 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. I will.

In the early stages of distribution, frontline health care workers and others, or those who are considered the most vulnerable, may be given higher priority. This is a process called targeted vaccination. This is a missing risk for people who may be considered “super spreaders”, such as public transport workers.

Joel Miller, a senior lecturer 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 restrictions

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

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

Even if the majority of the population is vaccinated, if people refrain from traveling, the number of infections may be further reduced.

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 infection 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 gets much better where the combination of measures is used.”

-Reports by Manas Sharma, Simon Scarr, and Jane Wardell. Written by Jane Wardell. Editing by Christopher Cushing