Pakistan study shows Covid-19 vaccines have low efficacy against UK variant

Patients who developed antibodies against original strain are still vulnerable to UK variant, DUHS researchers suggest

KARACHI:

As Pakistan continues its vaccination drive against Covid-19 amid the threat of different variations of the deadly contagion looming, local research confirmed that the current vaccines have some efficacy against the UK variant — considered more transmissible than the original Wuhan variant — but do not provide complete immunity, cautioning masses to continue adhering to standard operating procedures (SOPs).

Pakistan on Saturday recorded at least 3,876 confirmed cases of Covid-19 – the highest in eight months – as the third wave of the pandemic sweeps across the country. The country also recorded at least 42 fatalities from the virus in the last 24 hours.

The regions of Islamabad, Rawalpindi, Azad Jammu and Kashmir (AJK) and Punjab have in recent days reported a sharp rise in the number of Covid-19 cases. The UK strain of the virus – reportedly more lethal as well – is sweeping across these areas as the country grapples with the third wave of the pandemic.

Read more: Pakistanis aged 65 and above to be vaccinated against Covid-19 in March

A clinical investigation, published on March 11 in “Journal of Medical Virology”, showed that SARS-CoV-2/B117 – the UK variant – is spreading fast in Pakistan and variably reacting against the immunity gained by recovered persons from the previous infection in the country and across the globe.

A team of scholars from Dow University of Health Sciences (DUHS), comprising Sanya Shabbir, Anusha Amanullah, Fozia Raza, Muhammad Janees Imdad and Sahar Zahid and led by Dr Mushtaq Hussain, compared the UK variant with the Chinese origin variant and closely inspected both strains for their structural, pathogenic and immunological perspectives.

The team demonstrated that both these strains of viruses are binding with human cells with the same intensity through their spike protein. However, there are subtle differences in the spike proteins of both these strains of SARS-CoV-2 that can make the UK variant escape from antibodies generated against the original strain.

Colourised scanning electron micrograph of an apoptotic cell (greenish brown) heavily infected with SARS-COV-2 virus particles (pink), also known as novel coronavirus, isolated from a patient sample. Image captured and colour-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. National Institute of Allergy and Infectious Diseases. PHOTO: REUTERS/FILE

"Immunity is our inner defence system which develops certain agents – dubbed as antibodies – against diseases during our whole life. The number of antibodies increases as we are exposed to more and more bacterial viruses and other pathogens and sit in the blood serum," the team said in its findings.

It added that over a period of more than 15 months, the SARS-CoV-2 virus changed a lot by jumping from one group of people to another.

Pakistani researchers have identified at least 29 major changes between SARS-CoV-2 Wuhan and SARS-CoV-2 B117 versions but further probe is needed in this regard. However, they added that any patient infected with the Wuhan strain of SARS-CoV-2 and made antibodies against it, he or she is still vulnerable to the new UK variety of the virus.

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The B117 variant has caused a noticeable surge in the Covid-19 infections in the UK from November 2020 to January 2021 after strict lockdown was revoked in many regions.

The study stated that Covid-19 cases have sharply increased in the last two weeks in Pakistan, prompting government officials to declare it the third wave of the virus.

It said that B117 seemed to be the reason behind the sudden rise as many reported cases from Punjab are because of this variant strain of the SARS-CoV-2, adding that it may be escaping from the immunity developed against the original strain but also may be relatively more pathogenic.

Dow researchers observed major changes in spike protein and another protein called “orf8”. They suggested that orf8 gene of the B117 strain has changed to the extent that it may be forming two proteins. "The small protein emerges out of the cell while the big one remains in the cell."

Some 17 years ago, the phenomenon was observed in a rather more deadly wave of SARS-CoV in the year 2003, where the virus got two proteins from orf8 gene.

Dr Hussain has warned that those who have been vaccinated for Covid-19 must adhere to all the SOPs including social distancing and facemask.

“Current Covid-19 vaccines are effective against Wuhan strain of SARS-CoV-2 but relatively less against SARS-CoV-2 B117,” he added.

Dow’s investigation is also well supported by the recent findings published in prestigious science journal, Nature. It said that the antibodies developed against the original strain of Wuhan are not fully effective against the UK or B117 version. Importantly, both studies independently identified the same region of spike protein as the culprit for this immune evasion.

Another study led by researchers at the National Institute of Health in Islamabad showed the prevalence of more transmittable SARS-CoV-2 B117 in Pakistan. The team also suggested large scale genomic investigations and well-equipped testing labs across Pakistan to further identify the new variant in the population.

Another research paper in the journal “Cell” suggested that the UK variant is 30 to 60 per cent more infectious than the stains of the first wave of disease which could shed light on the third wave in Pakistan. This research also showed that current vaccines from, Pfizer, AstraZeneca and Moderna show less efficacy against the UK variant.

On the question of the reason behind the origin of this strain, Dr Hussain said that he is not absolutely sure how the new strain originated but it is the product of ongoing evolution in the viruses just like any other organism, only much faster in this case.

Scientific literature suggests that undefined immunotherapeutic measures are accelerating the rate of mutations in the virus, therefore, it is beneficial to provide corresponding immunotherapy to the patient according to the strain of the virus.

About the question of the current vaccines in changing scenario, he stressed that the current drive of vaccination must continue rather more aggressively but the vaccinated individuals should be made aware of the facts of the existing threat of prevailing viral strain and advised to continue following the SOPs.

He also said that scientific rigorous investigation will eventually triumph to develop a vaccine or immunotherapy that can provide protection against all the variations of the virus.