Herd Immunity against Corona

Experts pin hopes on vaccination

Mohammad Al Amin

13 February, 2021 12:00 AM printer

With the nationwide rollout of vaccine and a gradual fall in the positivity rate, Bangladesh will achieve herd immunity against Covid-19 soon, hope health experts.

They described the decline in the daily Covid-19 positivity rate over the past week as a progress that could help Bangladesh find its way out of the pandemic faster and more safely if it remains for at least two consecutive weeks.

Bringing the spread of the virus under control is the key to saving lives and reopening educational institutions and continuing other normal activities, the experts said.

“I hope we’ll achieve herd immunity against the coronavirus soon for developing antibody naturally and through vaccination. I urge the country’s people to receive the vaccine,” Dr Nazrul Islam, a member of the National Technical Advisory Committee on Covid-19, told the Daily Sun.

He, however, said there is no alternative to maintaining hygiene and following all necessary preventive measures like wearing masks and washing hands to stay protected from the coronavirus.

Talking to the Daily Sun, Dr ASM Alamgir, principal scientific officer of the Institute of Epidemiology, Disease Control and Research (IEDCR), claimed that the daily Covid-19 positivity rate has declined in the country as a result of maintaining preventive measures.

He also warned that if people do not abide by the preventive measures, the number of coronavirus infections may rise in the country anytime.

The official data show that Bangladesh is currently recording a low number of new cases and deaths from the coronavirus while the recovery rate has been on a steady rise.

According to the Directorate General of Health Services (DGHS), the Covid-19 positivity rate has been below 5 per cent for 22 days and under 3 per cent for the last eight days. 

A 2.82 per cent infection rate was recorded on Friday while 2.65pc on February 11, 2.59pc on February 10, 2.67pc on February 9, 2.30pc on February 8, 2.35pc on February 7, 2.51pc on February 6 and 2.79pc on February 5, it said.

The DGHS said 8,962 general beds out of total 10,323 dedicated for Covid-19 patients and 414 ICU beds among 582 were lying vacant across the country till Friday.

Of those, some 2,279 general beds out of total 3,233 and 195 ICU beds among 297 remained vacant in Dhaka while 554 out of total 687 general beds and 25 ICU beds among 45 were lying vacant in Chattogram.

The health experts hoped that the country’s Covid-19 situation will improve in the upcoming summer and things will become normal accordingly with the rollout of vaccine.                

Describing reasons behind the fall in the daily positivity rate, Dr Nazrul Islam, also a top virologist of the country, said, “Viral interference is one of the major causes for the decline in the infection rate in the country in winter. And another reason is developing antibody among people naturally.”

“I have a hypothesis that before the novel coronavirus, four other old respiratory viruses -- influenza, parainfluenza type 3, rhinovirus and respiratory syncytial virus -- existed in our country for long. During winter, these viruses dominated the human body without giving any chance to the new one,” he added.

Citing an IEDCR-icddr,b study conducted on samples collected till July 15 last year, Dr Nazrul, also former vice-chancellor of Bangabandhu Sheikh Mujib Medical University (BSMMU), said 6 per cent of people living in slums were infected with Covid-19 while 74 per cent had the antibody to fight that.

He expressed the hope that the coronavirus infections will not rise in the upcoming summer due to the countrywide Covid-19 vaccination and developing antibody naturally.

According to the World Health Organization (WHO), herd immunity happens when a population is immune either through vaccination or immunity developed through previous infection.

To safely achieve herd immunity against Covid-19, a substantial proportion of a population would need to be vaccinated, lowering the overall amount of virus able to spread in the whole population.

One of the aims with working towards herd immunity, also known as population immunity, is to keep vulnerable groups who cannot get vaccinated for health conditions safe and protected from the disease.

According to the DGHS, some 1,328,436 people have registered for the Covid-19 vaccination till 2:30pm on Friday while 542,309 people received their first doses of the vaccine till February 11. Vaccination remains closed on Friday.

The countrywide inoculation drive started on February 7 aiming to vaccinate 35 million people in the first phase.

In May, the World Health Organization (WHO) recommended that the positivity rate should be below 5 percent for at least two consecutive weeks before governments considered reopening.

The Health and Family Welfare Minister Zahid Maleque recently said the positivity rate has been near 3 per cent for many days. “We’re in a good situation and we have to try to maintain it."