The Omicron variant of SARS-CoV-2 has undergone fundamental changes that may explain its spread and disease. Researchers at the MRC-University of Glasgow Centre for Virus Research have used laboratory experiments and real world infection data to investigate Omicron.

The results, published as a pre-print study and not yet peer-reviewed, from laboratory tests showed that Omicron is largely unaffected by the antibodies provided by two doses of Covid-19 vaccine, but responses are improved by a third-dose booster.

This has been confirmed by analysis of real world infection data; Omicron escapes immunity from two vaccine doses, but three doses restores good levels of protection.

The escape from vaccine-induced immune responses means that over time, Omicron-specific vaccines would be required if disease severity was high, either directed at the general population or vulnerable groups.

Further, the study also provided evidence that Omicron has switched its route of entry into human cells, from cell surface fusion to cathepsin-dependent fusion within the endosome.

This fundamental biological shift is likely to influence Omicron spread and the types of cells it can hijack. These changes may also affect the pathogenesis and severity of disease, and researchers say they require further evaluation in population-based studies.

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First detected from South Africa and Botswana in late November last year, the virus has spread rapidly to more than 100 countries. It has also outpaced the previous Delta strain in many countries to become the dominant variant. The countries include the US, the UK, Italy and Portugal among others.

Increased intake of water and proper bed rest may help people recover fast from Covid-19 infections at home, according to an Australian expert.

On the other hand, the third wave has left many countries counting the rise in cases. Australia, India, China have seen a massive surge. And to understand the symptoms better, Australian professors have divulged into the new variant.

"Most people can manage at home, and can manage well," quoted Sydney based Professor and infectious diseases expert Robert Booy as saying.

"They will not get severe symptoms. They will get a cough, fever, lethargy and fatigue, and they will get better over a few days to a week.

"All you need is adequate hydration, water, bed rest, if you have analgesics for pain, and antipyretics for fever," Booy said.

Booy added people should look out for chest pain, worsening breathlessness, and lethargy as worrying symptoms that might need further medical attention, the report said.

"For people with chronic conditions or lung disease, some are given an oximeter, a special machine to measure the amount of oxygen in your blood, and you will need to go to hospital (or get medical attention) if your oxygen saturation is dropping," he said.

Booy also stated that rapid antigen tests (RATs) should be free across Australia. It comes as experts slammed the Scott Morrison government for "painting a rosy picture" of the new Omicron variant because it is less severe than Delta - as hospitals continue to fill around the country due to the sheer number of people infected, the report said.

Dr Stephen Parnis, an emergency physician from Melbourne, said although the new strain was less severe, the surging number of cases means a significant number of people will still be hospitalised.