More than 10 billion doses of coronavirus vaccines have now been administered, a significant milestone for such a short period of time since the launch (late 2020-early 2021 depending on the country) of the largest vaccination programme in human history, which has already vaccinated more than 60% of the world population (4.8 billion people) with at least one dose of one of the 20 or so existing vaccines.
But scientists warn that significant inequalities in access to vaccines remain (only 5.5% of people in poor countries have had two doses, while across Africa only 16% have had at least one dose) and it is very difficult to model the future of the Covid-19 pandemic and predict when it will end. However, they think it more likely that Omicron will not be the last variant that humanity will have to deal with, although the next one is expected to be even milder, though one cannot put one's hand in the fire for that.
The emergence of the even more contagious sub-variant BA.2 of Omicron (also known as Omicron 2), the different population composition and dynamics from country to country, the different vaccination strategies between countries, the different speeds and inequalities in vaccination programmes and thus the different levels of immunity between and within continents, the ambiguity about the pathogenicity of Omicron and its degree of immune escape, all make it difficult to make reliable predictions from scientific models, according to Nature.
Already, before the emergence of Omicron 2, the original Omicron (i.e. the hitherto dominant sub-variant of BA.1) had impressed everyone with its tremendous speed of spread and very high number of infections. Although the World Health Organisation (WHO) and some scientists have estimated that these huge numbers of - usually mild - Omicron cases may signal the end of the pandemic, as there will be a massive increase in levels of natural immunity combined with vaccine immunity, other scientists are more sceptical and warn that the situation remains volatile and difficult to model and therefore predict.
"It's moving so fast that it gives us very little time to prepare any kind of response. So decisions have to be made under huge uncertainty," said infectious disease modelling expert Dr Graham Medley of the London School of Hygiene and Tropical Medicine.
Omicron infection numbers - even before Omicron 2- can double in less than two days, much faster than previous variants. "We haven't seen similar speed before, which means that even with vaccines we can't find a solution to all of this. Even if we vaccinate everyone, it takes two weeks for the vaccine to work and by then we're already in trouble," said health data analyst Christina Page of University College London (UCL).
Although vaccines continue to provide significant (not absolute) protection against serious disease, hospitalisation and death, according to her, "there is a sense that none of the vaccines are going to provide lasting protection against this infection." British virologist Julian Tang agrees: "I don't think vaccines are the way this pandemic is going to end."
"It's not the last variant."
So how will the end of the pandemic come? Not with Omicron, several researchers predict. "This will not be the last variant and the next one will have its own characteristics," Dr Medley reckons."
Since the SARS-CoV-2 coronavirus is unlikely to disappear completely, the prevailing view is that Covid-19 will remain as an endemic disease, but endemicity - that is, "living with the virus" without restrictions - is a rather vague concept that means different things to different people. Consequently, it is difficult to model (predict) accurately, as even the best models struggle to make predictions beyond a time horizon of a few weeks. Also, predicting endemicity inevitably involves an assessment of how many Covid-19 deaths societies will be willing to tolerate in the future as "normal" (as is more or less the case with flu victims every year).
According to infectious disease epidemiologist Mark Woolhouse of the University of Edinburgh, Covid-19 will only become truly endemic when most adults are protected from severe infection, because they will have been exposed to coronavirus many times as children and so will have developed considerable natural immunity. Which will obviously take decades and mean that many current elderly people who were not exposed to the virus in childhood will remain vulnerable and may need ongoing vaccinations.
Furthermore, there are no guarantees that the next post-Omicron variant will be milder. However, most scientists are hopeful that it will be, as that seems to have been the case with successive variants of the coronavirus so far.
Source: Proto Thema
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