PETALING JAYA, July 15 — After two-and-a-half years of the pandemic, we might be ready to go back to normalcy — but health experts warn Covid-19 is far from over.
Covid-19 cases have begun to rise again globally, partly fuelled by new and more infectious sub-variants of the virus.
Owing to these mutations, as well as the risk of overburdening healthcare systems as well as the speed of new infections, the World Health Organization’s (WHO) Emergency Committee declared that Covid-19 is still a high alert public health emergency.
“The virus is running freely and countries are not effectively managing the disease burden based on their capacity, in terms of both hospitalisation for acute cases and the expanding number of people with post Covid-19 condition — often referred to as long-covid,” said WHO Director-General Tedros Adhanom Ghebreyesus on Tuesday.
Closer to home, Health Minister Khairy Jamaluddin last Friday warned that BA.5’s entry into Malaysia was concerning as it was the most contagious Covid-19 variant to date based on current global data.
Mutations and variants
Early on in the pandemic, studies found that most people who contracted the Covid-19 virus developed some immunity against the virus, which could last between 30 and 90 days.
Emerging research however, shows that the Omicron variant, especially the BA.4 and BA.5 sub-variants, are more likely to evade the immunity built up from past infections.
American physician Dr Eric Topol called BA.5 the “worst variant we have seen so far” due to its “severity of immune evasion and transmissibility”.
— Eric Topol (@EricTopol) July 12, 2022
“There’s clearly more room for the virus to evolve, get more fit, gain advantages as an immune escape artist and more efficiently infect cells,” Topol wrote in his newsletter Ground Truths on Monday.
“Yet we are watching its accelerated evolution akin to the behaviour of a Formula One race car lapping around the track with humans in the stands.”
What makes the Omicron variant particularly concerning is its ability to tolerate changes in its spike protein, the part of the virus that infects cells.
A recent study, published in the journal Nature on July 5, looked into how different Omicron sub-variants reacted to vaccines — it found that the BA.4 and BA.5 are at least four times more resistant to antibodies in vaccinated individuals.
At the same time, experts are concerned by the various other Omicron variants in the mix.
In May, the BA.2.75 variant was detected in India, and has since been found in several other countries including Australia, Canada, and the UK.
This number of mutations present in this BA.2.75 variant, dubbed the “Centaurus”, has alarmed some virologists.
“It’s hard to predict the effect of that many mutations appearing together,” Imperial College London virologist Dr Tom Peacock told The Guardian on Wednesday.
“It gives the virus a bit of a ‘wildcard’ property where the sum of the parts could be worse than the parts individually.
“It is definitely a potential candidate for what comes after BA.5.”
Risks of reinfection
While experts are uncertain of whether these new variants led to more severe disease, vaccines and treatments currently available are still able to mitigate the worst effects of the disease.
Ubat antiviral Paxlovid mampu mengelakkan jangkitan COVID-19 daripada menjadi lebih teruk. Bagi yang berisiko tinggi dan mengalami gejala ringan hingga sederhana, anda boleh ke klinik atau hospital berdekatan untuk penilaian dan jika layak, boleh diberikan Paxlovid. pic.twitter.com/u1Bv2jwAI3
— Khairy Jamaluddin (@Khairykj) July 15, 2022
However, the ability of the virus to escape immunity means that reinfections are becoming common.
The Australian Health Protection Principal Committee recently recommended that the reinfection period be reduced from 12 weeks to 28 days, owing to these new sub-variants of the virus.
“BA.4 and BA.5 are associated with increased immune escape and we are likely to see rates of reinfection rise among those who have previously been infected with an earlier Covid-19 variant and those who are up to date with their vaccinations,” the committee said in a statement last Friday.
A visualisation of the Covid-19 virus. Experts say new variants of the virus have shown to be more able to get around immunity built up from past infections. — Picture via Unsplash/ Fusion Medical Animation
Several Australian states formally adopted this advice this week, urging people to test again if they experience symptoms 28 days after recovering from Covid-19.
“We’re urging people who have recently had Covid-19, even if they left isolation in the past four weeks, not to be complacent,” New South Wales chief health officer Kerry Chant told The Guardian on Tuesday.
As the risk of reinfection increases, scientists aren’t quite certain if there are cumulative effects of contracting mild bouts of Covid-19 again and again.
A recent pre-print study (meaning it has yet to be peer-reviewed) found that those who have had two or more Covid-19 infections had double the risk of developing conditions affecting various organs, including the heart, lungs and kidneys.