Nigeria sees herd-immunity pick up without COVID-19 vaccines

Nigeria might be off to a real path of recovery with evidence of herd-immunity build-up confirmed in few states, including the epicentre of COVID-19, Lagos.

In a survey for the presence of antibodies against SARS-CoV-2 in the blood samples of 10,000 people, the Nigeria Centre for Disease Control (NCDC) found that one in five had been infected, recovered and developed antibody – a natural means of achieving herd immunity.

Findings released on Monday indicate that 23 percent of surveyed individuals in Lagos State had antibody presence, 19 percent in Nasarawa, and 9 percent in Gombe.

A higher rate of infection was detected in more males than females, more urban residents than rural, and from ages 18 to 64. Variations were also noticed across the local government areas within the states.

Antibodies are protective protein produced by the immune system in response to viruses such as COVID-19.

This could potentially boost Nigeria’s chances of flattening the curve quicker, in addition to administering vaccines for herd immunity.

Herd immunity means boosting the immunity among people to a point where the proportion of those susceptible to the disease become significantly lower to those who can’t be infected.

It can be achieved naturally by having a large portion of the population recover from an infection or simply through vaccines.

Using the vaccination method, the Federal Government plans to cover 70 percent of its population estimated at 206.1 million by the United Nations.

Vaccinating 70 percent means 144.2 million people will get at least a two-dose regimen, amounting to over 288.5 million doses required. But so far, only 16 million doses of Astrazeneca have been pledged to Nigeria.

However, the results from the survey is not absolute as the NCDC notes that antibodies might have waned completely in people infected many months before the survey was conducted. The pandemic became a domestic crisis about a year ago.

“SARS-CoV-2 emerged only one year ago and antibody response according to the severity of the infection and the duration of antibody persistence is not yet completely understood,” said the released signed by Chike Ihekweazu, NCDC’s director-general.

The report survey further indicates that the rates of infection are higher than those reported through the national surveillance system and reveal that the spread of infection in the states surveyed is wider than is obvious from surveillance activities, the centre stated further.

The survey is expected to be expanded to more states from the North-West and South-South zones.

However, vaccines remain of huge benefit against the pandemic as immunity from antibodies may not assure full coverage of herd immunity, Saliu Oseni, former chairman, Nigeria Medical Association, Lagos chapter, says.

“Most studies have shown that you can be re-infected. Nobody is really sure of how long immunity can be retained after vaccination. So, the best thing is not to take a risk. A vaccine will still be of advantage.”

According to a molecular biologist who does not want to be mentioned, how long that immunity will last is a concern that should prompt quick actions on the vaccine.

“Immunity is building up, but to achieve by natural immunity will be catastrophic. You need about 75 percent of the population to be infected. How many do you have to kill? If it lasts for six months, it is not something we can rely on.”