Can herd immunity end the coronavirus pandemic? Expert explains how

There has been a lot of talk about "herd immunity" and how it might be the answer to ending the coronavirus disease 2019 (COVID-19) pandemic.

The concept is simple: when a large number of people develops resistance against an illness, fewer people get sick and it becomes harder for the disease to spread.

If that sounds like a solution, that’s because theoretically, it is. But there’s a caveat.

"Achieving herd immunity is needed in order to stop the spread of COVID-19. How and when we can achieve herd immunity is the question," said Kim Carmela Co, an assistant professor of epidemiology at the UP College of Public Health.

According to the Centers for Disease Control and Prevention (CDC), there are two ways of developing immunity to a disease: through prior illness or through vaccination.

Immunity through prior illness

When a person gets sick, their immune system produces antibodies to fight off toxins such as bacteria or viruses. Those antibodies usually remain in the blood after they recover, thus giving them immunity.

In the case of COVID-19, however, it may not be a good idea to expose people to the virus just to develop herd immunity.

"Simply allowing the virus to spread in the population is not an acceptable strategy because estimates indicate that around 2-4 people per 100 cases of COVID-19 may die," Co told GMA News Online.

If the number of infected patients surge up to a level that the healthcare system may no longer be able to handle, this will result to even more fatalities.

"In addition, we still have to learn more about the immunity resulting from an active infection - for example on whether it leads to temporary or lifelong immunity," Co said.

Experts say it is still not clear if a recovered COVID-19 patient has successfully developed an immunity to the disease. There are also reports of recovered patients once again testing positive for the virus.

Immunity through vaccination

Vaccination, meanwhile, involves the use of a "killed or weakened infectious organism" to develop antibodies without contracting the disease itself.

"Achieving herd immunity through high vaccination rates is the main strategy for controlling infectious diseases like measles and polio," Co said.

The global scientific community is racing against time to develop a COVID-19 vaccine as soon as possible.

The World Health Organization (WHO) earlier said a vaccine could be available in 18 months, but other experts have reservations.

The fastest vaccine to be developed in history, the mumps vaccine, took four years from getting samples all the way to licensing.

READ: The development of COVID-19 vaccine explained

However, Co said remaining on lockdown is "not a sustainable or long term approach."

Until a vaccine is rolled out, she suggested alternating between loosening and tightening of restrictions to keep the number of infections under control.

She added that "special protection measures" must be extended towards vulnerable groups, such as the elderly and those with underlying health issues.

"This cycle of relaxation and implementation of measures will likely be continued until herd immunity is achieved through the production and distribution of an effective vaccine," Co said. —MGP, GMA News