ECONOMYNEXT – Vaccination against COVID-19 will help bring the death rate down and minimise severe disease but the jab can take weeks to be fully effective and vaccinated people can still spread the virus as asymptomatic carriers, a leading Sri Lankan microbiologist said.
Neelika Malavige, Professor in Microbiology at the Department of Immunology and Molecular Medicine, Faculty of Medicine, University of Sri Jayewardenepura, in a Government Information Department interview this morning (19) urged vaccinated Sri Lankans to stick to health protocols such as masking and regular hand washing.
“No one gets immediate protection right after the jab. It takes about 21 days for the body to produce antibodies after the first dose of AstraZeneca (Covishield). One dose does not provide sufficient protection, which is why we give two,” said Malavige.
Sinopharm also provides considerable protection but only two weeks after the second jab, the professor said. Sri Lanka has decided to give the two doses of the Chinese vaccine four weeks apart.
“In the meantime, you can still get infected and infect others,” she warned.
Taking a new wave of COVID-19 in Singapore as an example, Malavige said vaccinated airport employees were found to have spread the highly transmissible Indian strain of the virus in the city state.
“Everyone at the airport had received the Pfizer jab, so even when they tested positive for COVID-19, they didn’t report severe symptoms. But they still got infected and, as asymptomatic patients, carried the virus into the wider Singaporean society,” she said.
Echoing Malavige, Director of the Infectious Diseases Hospital Dr Ananda Wijewickrama said the primary objective of vaccination is to prevent critical conditions and death.
“People who get the jab can still get infected, but they have a lower chance of developing critical symptoms. It is important to follow health guidelines because we can be vaccinated and still spread it,” he said.
Six variants of SARS-CoV-2, the virus that causes COVID-19, three of which are variants of concern as classified by the World Health Organisation (WHO), have been detected in Sri Lanka. The variants of concern, B.1.1.7 (UK), B.1.617 (India) and B.1.351 (South Africa), experts say, are more contagious, cause more severe disease, show significant reduction in neutralisation by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.
As per genome sequencing tests carried out by the Allergy Immunology and Cell Biology Unit of the University of Sri Jayawardenepura, the six variants were all detected both in quarantine centres from returnees from abroad and from community.
B.1.411 – Sri Lankan variant
A mutated variant that has only been detected in Sri Lanka suspected to have been mutated from the original COVID-19 virus. The virus has been mainly detected in the Batticaloa district and in the Western Province and was the dominant variant before identifying the UK variant.
According to health authorities, this virus has a lower transmissibility and mortality rate making most of the patients asymptomatic.
B.1.428 – Denmark/ European/ Middle East variant
The variant that widely spread in Middle East and, according to the Epidemiology Unit, most of the returnees from abroad mainly coming from Middle Eastern countries were carrying the virus. This variant too has a low mortality rate, and most patients are asymptomatic. The variant has been detected only in Jaffana in the Nallur cluster.
B.1.525 – Nigerian variant
Officials said the variant was mainly identified in Banadaragama and Colombo areas and no further spreadi of the virus has been detected in the community.
B.1.351 – South African Variant (variant of concern)
This is a variant of concern with E484K mutation that has a higher transmissibility rate and a mortality rate. It was predominantly found in South Africa and also identified in several other countries including Germany, France, US and Sweden.
Due to mutations, concerns about vaccine efficacy arose. However, health authorities said the current vaccines used globally have a higher efficacy rate towards this strain.
B.1.617 – Indian variant (variant of concern)
The variant responsible for the aggressive surge in fatality cases and number of patients in India was identified from a returnee in a quarantine center. The variant shows several spike mutation in the virus.
According to BBC reports the transmissibility of and the mortality rate of the virus has been not identified yet. It has caused more than 4,000 deaths and over 350,000 cases per day in India.
Health officials said the variant has not been detected in the community in Sri Lanka so far.
B.1.1.7 – UK/Kent variant (variant of Concern)
The so called UK strain is the current dominant variant in Sri Lanka responsible for the rapid increase in cases. The variant is said to be 50 percent more transmissible has a 55 percent increase in mortality than the original virus.
The variant was first detected in Sri Lanka in January 13, 2021, from a British national who arrived in Colombo. After that according to the Allergy Immunology and Cell Biology Unit of the University of Sri Jayawardenepura, the variant was detected in several construction workers in Borelasgamuawa on April 08, though the same university had earlier said it was found in the community in late January/early February. The university later clarified that subsequent contact tracing had shown otherwise.
The strain was later identified within the Colombo Municipal Council (CMC) area, Homagama and Boleresgamuwa in the Colombo district, Polpithigama, Kuliyapitiya, Nikaweratiya, Ganewatta, Ambalanpola, Giriulla, Pannala and Wariyapola in Kurunegala district, Agalawatta, Pimbura, Panadura, Palindaruwa and Banadaragama in Kalutara district, Panduwasnuwara, Kansy and Hingurakoda in Kandy district, Medirigiriya in Polonnaruwa district and Mannar town in Mannar district.
Sri Lanka currently uses three types of COVID-19 vaccines: t he Oxford AstarZeneca manufactured in India under the brand name Covishield, the Chinese manufactured Sinopharm and the Russian Sputnik V.
Director of Allergy Immunology and Cell Biology Unit of the University of Sri Jayawardenepura Dr Chandima Jeewandara told the privately owned ABC media network that all three vaccines have been proven to be effective against the variants present in the country.
“International research has indicated that the efficacy rate can be changed with these mutations. However, any vaccine that shows an efficacy rate more than 50 percent is considered to be a successful
vaccine and all three vaccines are proved to have a higher efficacy rate at the moment,” Jeewandara said.
Jeewandara predicted that Sri Lanka’s ongoing wave of COVID-19, with over 2,500 cases reported a day, will likely be contained by August this year.
“The virus has not changed the way it’s infecting people,” he said.
Vaccination and strict adherence to health protocols will contribute chiefly to containing the spread.
“We should provide at least one type of vaccine to the community. If the vaccine is being given in your area get it immediately, Wear the mask, keep social distance and avoid any gatherings,” he said.
“The next moth is crucial to Sri Lanka. We expect this wave to be controlled by August,” he added.
Jeewandara said there is no guarantee the virus will disappear. Vaccination is the one strategy to take control of the situation, he added. (Colombo/ May 19/2021)