{"id":32643,"date":"2021-09-17T07:08:09","date_gmt":"2021-09-17T03:08:09","guid":{"rendered":"http:\/\/www.mauritiustimes.com\/mt\/?p=32643"},"modified":"2021-09-17T07:08:09","modified_gmt":"2021-09-17T03:08:09","slug":"how-will-the-covid-pandemic-end","status":"publish","type":"post","link":"https:\/\/www.mauritiustimes.com\/mt\/how-will-the-covid-pandemic-end\/","title":{"rendered":"How will the Covid pandemic end?"},"content":{"rendered":"

\"\"<\/em><\/span><\/h4>\n

<\/h4>\n

Countries yet to experience major outbreaks will probably see big rises in cases, even if their vaccine programmes are successful<\/em><\/span><\/h4>\n

\"\"Alfonso Fabio Iozzino\/Alamy Stock Photo<\/span><\/span><\/p>\n

After over 18 months of this pandemic, with the social distancing, mask wearing and on-off lockdowns, what we all want to know more than anything else is when it will all be over and how it will end. While nothing is certain, we have a lot of evidence on which to build some realistic expectations about how the pandemic will progress over the next year or so.<\/span><\/p>\n

Covid-19 may not be the first time a coronavirus has caused a dreadful global pandemic. It\u2019s been\u00a0hypothesised\u00a0that the \u201cRussian flu\u201d, which emerged in 1889, wasn\u2019t actually influenza, but was caused by another coronavirus,\u00a0OC43.<\/span><\/p>\n

The Russian flu pandemic caused four or five waves of disease over the following five years, after which it seemed to disappear. In England and Wales, most of the excess deaths it caused\u00a0were restricted to 1890-91. OC43, the potential cause, still circulates today, though rarely causes severe disease.<\/span><\/p>\n

Current evidence suggests SARS-CoV-2 \u2013 the coronavirus that causes Covid-19 \u2013 is also here to stay, a conclusion reached\u00a0some months ago\u00a0by many scientists working on the virus. Neither vaccines nor natural infection will stop the virus from spreading.<\/span><\/p>\n

While vaccines do\u00a0reduce transmission, they don\u2019t block infection to a high enough degree to eradicate the virus. Even before the delta variant arrived, we were seeing double-vaccinated people both catching the virus and\u00a0spreading it to others. As vaccines are\u00a0somewhat less effective\u00a0at combating delta compared to other forms of the virus, the possibility of infection post-vaccination has grown.<\/span><\/p>\n

Immunity to infection also starts to wane within\u00a0weeks of receiving a second vaccine dose. And because immunity to infection is neither absolute nor permanent, herd immunity is unachievable. What this means is that Covid-19 is likely to become endemic, with daily infection rates\u00a0plateauing\u00a0depending on how much immunity and mixing there is across the population.<\/span><\/p>\n

The other human coronaviruses cause repeat infections on average\u00a0every three to six years. If SARS-CoV-2 ends up behaving the same way, this suggests that in the UK between one-sixth and one-third of people \u2013 or between 11 and 22 million \u2013 could get infected with it every year on average, or 30,000 to 60,000 a day. But that is not as scary as it sounds.<\/span><\/p>\n

Yes,\u00a0emerging research\u00a0(still in preprint, and so awaiting review by other scientists) does suggest that immune protection against\u00a0developing symptomatic Covid-19\u00a0appears to wane. However, protection against severe disease \u2013 generated either by immunisation or natural infection \u2013 is\u00a0much longer lasting. It also\u00a0doesn\u2019t appear\u00a0to be lost when facing new variants.<\/span><\/p>\n

Indeed, for the other human coronaviruses, the vast majority of infections are either asymptomatic or at worst a mild cold. The signs are there to suggest that Covid-19 may end up being the same.<\/span><\/p>\n

A pandemic with multiple endings<\/strong><\/span><\/p>\n

How Covid-19 will end will vary from one country to another, depending largely on the proportion of people immunised and how much infection has occurred (and so how much natural immunity has built up) since the start of the pandemic.<\/span><\/p>\n

In the UK and other countries with high vaccine coverage and also high numbers of past cases, most people will have some form of immunity to the virus. In England, for example, it\u2019s\u00a0estimated\u00a0that at the beginning of September over 94% of the adult population had Covid-19 antibodies.<\/span><\/p>\n

Among those with prior immunity, it\u2019s been shown that Covid-19\u00a0tends to be less severe. And as more people\u2019s immunity is boosted over time by natural reinfections or booster immunisations, we can expect an increasing proportion of new infections to be asymptomatic or at worst cause mild illness. The virus will remain with us, but the disease will become part of our history.<\/span><\/p>\n

But in countries without much prior illness, even with high vaccine coverage, many people will remain susceptible. Even in countries with the highest vaccine coverage worldwide\u00a0over 10% of people\u00a0are yet to receive a vaccine. Virtually everyone who has not been vaccinated is likely to catch the virus. When infected, they will be as much at risk of severe disease and death (depending on their age and medical status) as at any time during the pandemic.<\/span><\/p>\n

And in these countries, opening up will almost certainly lead to exponential growth of infections due to the large number of people with no immunity. And as the amount of virus circulating rises, there will be\u00a0more cases in vaccinated people\u00a0too, given that vaccines aren\u2019t 100% protective. Although Covid-19 tends to be less severe in vaccinated people, some do still get very ill \u2013 and these countries may see a sizeable number of vaccinated people needing hospital care.<\/span><\/p>\n

When these countries choose to open up will also have a critical impact. Too soon and many people will still be waiting to be vaccinated. Too late and the effectiveness of vaccines in the already-vaccinated\u00a0may have started to wane.<\/span><\/p>\n

Nevertheless, the key lesson from the Russian flu is that Covid-19 will become less relevant over the coming months, and that most countries are almost certainly over the worst of the pandemic. But it is still critical that vaccines are offered to the world\u2019s remaining vulnerable populations.<\/span><\/p>\n

It\u2019s becoming clear that the main impact of vaccination won\u2019t be to stop people from catching SARS-CoV-2, but to reduce the severity of infection the first-time people encounter the virus. If people have already been through their first or second natural infection, vaccines will add relatively little protection. To offer the biggest reduction in severe disease, vaccines need to be rolled out to as many people as possible now.<\/span><\/p>\n

Paul Hunter<\/span>
\n<\/strong>Professor of Medicine,
\nUniversity of East Anglia<\/p>\n

\n

* Published in print edition on 17 September 2021<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

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