[ad_1]
SYDNEY: The new coronavirus pandemic has brought “herd immunity” to the public consciousness, raising hopes that the phenomenon can help curb or even end the outbreak.
Herd immunity refers to a large part of a community that develops some degree of immunity to a virus, reducing the spread from person to person. As a result, the entire community gets protection, not just those who are immune.
NATURAL INFECTION VS VACCINATION
There are two routes to herd immunity: natural infection or vaccination.
Natural infection refers to when a large number of people have had an illness and have recovered. However, the extent of protection through natural infection with the new coronavirus is unknown. Furthermore, more people would die waiting for herd immunity than if a vaccine were produced.
“The risk is not acceptable,” said Catherine Bennett, chair of epidemiology at the Deakin University School of Health in Melbourne. “We cannot allow infected people to achieve herd immunity when we know so little about the long-term effects.”
Vaccination can provide generalized immunity more quickly and reliably.
READ: In the coronavirus vaccine race, China inoculates thousands before trials are completed
There is no vaccine for COVID-19, the disease caused by the new coronavirus, although trials are underway at different stages around the world. Typically, it takes several years to identify, test, produce, and distribute a vaccine for public use. Vaccine manufacturers hope to dramatically compress that schedule for COVID-19 through faster trials and manufacturing at scale even before the products have proven successful.
Experts believe that if no other measures are taken, herd immunity could be activated when between 50% and 70% of the population obtain immunity through vaccination. The exact level depends on the vaccine’s effectiveness rate, which experts say will be 70 percent at best.
READ: China’s coronavirus vaccine may be ready for the public in November: Official
BALANCE OF VACCINE DISTRIBUTION
The way a vaccine is distributed has implications for efficacy. If it is shared unevenly, for example if the rich have greater access than those in poorer places, that would create safe groups but leave large areas of susceptible people.
In the early stages of distribution, health workers and other people on the front line, or those considered most vulnerable, can be given higher priority, a process known as targeted vaccination. That runs the risk of losing people who could be considered “super spreaders,” such as public transportation workers.
“We need to be sure that we distribute the vaccine equitably among the population,” said Joel Miller, senior lecturer in applied mathematics at La Trobe University in Melbourne, who uses mathematical modeling to help governments and nonprofits. to formulate policies to control infectious diseases.
READ: Singapore’s race for a vaccine: can it be won before the second wave of COVID-19?
MOVEMENT RESTRICTIONS
The movement of people also has implications for the spread of a virus.
At lower vaccination levels, the number of people who eventually become infected is similar in a group of people who mix and travel a lot, and in a group of people who are relatively static. However, the spread is much slower in a static population, which is why governments around the world impose blocking measures.
Even when a high percentage of the population is vaccinated, the number of infections can be further reduced if people refrain from traveling.
READ: When can you get a COVID-19 vaccine? Five things you should know
WHILE WE WAIT
The new coronavirus is mainly transmitted through droplets expelled when a person coughs, sneezes or even speaks.
Until a vaccine is developed, the use of masks, physical distancing, and hand hygiene can help reduce transmission and help build herd immunity.
Epidemiologists largely agree that a combined approach is essential, since the first vaccines to be marketed are likely not to be 100% effective.
“It’s about adding layers,” said Bennett of Deakin University. “It gives us additional protection against community spread. The situation is much better in places where a combination of measures is used.”
CHECK THIS: Our comprehensive coverage of the coronavirus outbreak and its developments
Download our app or subscribe to our Telegram channel for the latest updates on the coronavirus outbreak: https://cna.asia/telegram
