Almost a year into the pandemic, Bangladesh kicked off a mass vaccination campaign against the coronavirus in February with hopes of vanquishing the disease that decimated lives and livelihoods, bdnews24.com reports.
Nurse Runu Veronica Costa became the first Bangladeshi to receive the vaccine and despite some hesitancy early on, millions have since followed suit.
Nine months on, many of the vaccinated are wondering if they need a third shot to boost their immunity against Covid-19 as the pandemic wears on, even though a large swath of the population is yet to get the first dose.
Some countries have made booster shots available after studies showed that the protection offered by vaccines wanes over time.
The government has set its vaccination target at nearly 140 million people, or 80 per cent of the population. So far, it has only administered about 42 million first doses and nearly 27 million second doses of the vaccine, which means 25 per cent of the population has received at least one vaccine shot.
Bangladeshi experts and authorities are currently not in favour of a booster dose programme because of the limited vaccine stock.
And still, there is no consensus among scientists that booster doses are necessary. The World Health Organization wants the most vulnerable people worldwide to be fully vaccinated first.
However, many developing nations, along with the rich countries, have begun administering booster doses to their citizens. They include the United States, the United Kingdom and China.
WHAT OTHER COUNTRIES ARE DOING
After launching the immunisation drive with the Oxford-AstraZeneca shot, the government has predominantly used the Sinopharm vaccine from China, along with the US-made Pfizer-BioNTech and Moderna doses ever since.
But researchers in Britain found that protection against Covid-19 offered by two doses of the Pfizer and the AstraZeneca vaccines begins to fade within six months.
After five to six months, the effectiveness of the second Pfizer jab fell from 88 per cent to 74 per cent, an analysis of data collected in Britain's ZOE COVID study showed in August.
For the AstraZeneca vaccine, the effectiveness fell from 77 per cent to 67 per cent after four to five months.
A more recent study in the UK found vaccinated contacts who tested positive for Covid-19 on average had received their shots longer ago than those who tested negative, which the authors said was evidence of waning immunity and supported the need for booster shots.
"Immunity wanes over time, it is imperfect, so you still get transmission happening, and that is why the booster programme is so important," said epidemiologist Neil Ferguson.
Booster doses are currently being rolled out to everyone aged 50 and above in Britain, as well as health care workers and the clinically vulnerable, six months after their second doses. So far, 6.7 million booster doses, which is enough to cover 10 per cent of the total population, have been administered.
The US Center for Disease Control now recommends that everyone aged 18 and above, who got the Johnson & Johnson vaccine at least two months earlier, should take any one of the authorised Covid-19 boosters.
People who are 65 or older and got either of the messenger RNA, or mRNA, vaccines from Pfizer or Moderna who are 65 or older, are eligible for a booster shot, as are those between the ages of 18 and 64, who are at risk because of where they work or live or because of health issues that put them at risk of serious illness, such as diabetes.
As of Oct 27, 0.93 per cent of the global population have received a booster dose of the coronavirus vaccine, according to Our World in Data.
WHAT SHOULD BANGLADESH DO?
Dr Firdausi Qadri, a senior researcher at the International Centre for Diarrhoeal Disease Research, Bangladesh, does not believe everyone in Bangladesh needs a booster dose at present. She believes it is “premature” to roll out the booster shots before administering two doses to all.
“We’ll need to give (the booster shot idea) more thought. Maybe booster doses will be needed for some people who are at high risk,” Dr Firdausi said, adding that the icddr,b has launched a study jointly with the government’s disease control agency IEDCR to determine whether booster doses are really needed in Bangladesh.
“If we administer booster doses now, some people may miss out on their vaccines. We need to lower the age limit for vaccines as schools and colleges have reopened.”
“Antibodies produced by a vaccine shot decrease after a certain period of time. But the memory cell remains and it gets reactivated and creates antibodies fast when the virus attacks. The drop in antibodies does not necessarily mean the vaccine is not working,” said the Ramon Magsaysay Award-winning scientist.
Dr Be-nazir Ahmed, a member of the National Immunisation Technical Advisory Group or NITAG, said they are not considering booster doses for Bangladeshis right now.
“How can we think about booster doses when a large portion of the population has not yet received their second dose of the vaccine? We will consider this option only after 80 per cent of the population is fully vaccinated.”
Professor Dr Meerjady Sabrina Flora, an additional DG at the Directorate General of Health Services and president of the National Vaccine Deployment Committee, said the directorate is not thinking about booster doses either.
“There is no specific information on when a booster dose is required after receiving the vaccine. The WHO has not yet recommended booster doses. There are discussions about giving booster doses to people at high risk. It is usually given after six months. The whole matter depends on whether most of the population are fully vaccinated.”
She ruled out the possibility of approving booster doses imported by private companies.
“This is because people will need to pay for the vaccine if they are administered privately, whereas the government is giving it for free. The government’s plan has ensured the purchase of enough doses for 80 percent of the population.”
[With details from Reuters and The New York Times]