Vaccines key to recovery

HERD IMMUNITY: GOAL WILL NOT BE ACHIEVED WITHOUT JABS – EXPERT

‘We also don’t even know how long it lasts in humans after they have become infected.’

Herd immunity to deadly, infectious diseases cannot work without a vaccine, unless you allow millions to die unnecessarily. This was according to epidemiologist Jo Barnes in the wake of heightened scepticism about the global Covid-19 vaccination drive.

While some have theorised that one simply needed to let populations become infected without lockdown restrictions in order to speed up the process of herd immunity, Barnes warned that nowhere had this ever been carried out without dire consequences.

Herd immunity is when a large part of the population of an area is immune to a specific disease. Herd immunity threshold refers to the percentage of a population which needs to become immune in order to eradicate a disease.

“There are ethical and scientific reasons why herd immunity shouldn’t be pursued through allowing people to become infected, but also we don’t even know how long that immunity lasts in humans after they have become infected with Covid-19,” she said.

Although there was no consensus on the quorum for herd immunity, the SA government was targeting 67% of the population.

Drug manufacturer Pfizer’s vaccine had been authorised for persons aged 16 and up while Moderna’s vaccine was currently authorised for ages 18 and up.

As of 2018, SA had over 26 million inhabitants under the age of 19, so it remained to be seen which demographic would make up the bulk of recipients.

On Tuesday the health department said it was targeting 40 million people in the country.

Barnes pointed out that statistically it was unlikely there were that many eligible adults in SA.

According to the World Health Organisation (WHO), scientists were still learning about immunity to Covid-19.

While most people infected developed an immune response within the first few weeks, it was unclear how strong or lasting that immune response was, or how it differed for different people. Some have been infected with Covid-19 for a second time.

Given that the pandemic was barely a year old, it would not be possible to know how much of a population was immune and for how long that immunity would last. –

Picture: Reuters TEST ON THE GO. A health worker approaches a motorist at a Covid-19 drive-thru testing site of a Dis-Chem pharmacy in Midrand this week.