Why The Current Surge In Cases Is A Problem For Some Countries But Not Others

Just as it appeared that COVID cases would begin to decline after the January highs, infections are again rising around the globe. This latest surge is mainly due to the rise in infectious diseases. BA.2 sub-lineagethe omicron version, which has been increasing in popularity ever since Christmas.

In the UK, increased social mixing and waning vaccine effectiveness – even in those who have had a booster dose – are contributing to this rise. But we’re also seeing huge spikes in areas that had previously kept themselves fairly COVID-free – New Zealand, Hong Kong and South KoreaFor example,

These cases are higher than those in Europe during the worst. However, these countries are implementing strict zero COVID policies. There are tight border controls, and strict internal measures to reduce infections. In areas with tighter restrictions, the highly infectious new variant has a greater impact. But why?

Zero cases equals delayed cases

Long before COVID, it was known that non-pharmaceutical control measures – whether within a countryOr at its border – rarely stop a pandemic spreading. Usually, these things – lockdowns, quarantines and so on – only delay a disease’s spread. This may not be enough to stop the spread of infection and reduce pressure on the health system. It can also be used to reduce illness and death by delaying many infections until treatment is available.

Immunity, which can be induced or vaccinated, is the most important factor in disease prevention. Both are important. As I pointed out last summerThe extent of the COVID infection in any country and the proportion of those who have been vaccinated will determine if the pandemic is over.

Breakthrough infections in those who have been vaccinated will increase their immunity, while an infection in the unvaccinated provides protection that is not possible. Immunity following an infection is better than immunity from a booster vaccination, especially once it has occurred. 90 days have passedSince being vaccinated.

This helps explain why some countries are able to handle outbreaks more effectively than others. The UK has a poor record in vaccination coverage. majority of peopleMany people have been bitten by COVID multiple times. While cases are not as high as those in the Pacific countries, they are still quite high. rates of deathBoth severe and mild disease are still at a low level.

Comparatively, countries that have followed a zero COVID strategy are seeing an increase in deaths and infections as they open up. This is despite having high vaccination coverage. Because there are no prior infections, immunity is lower across the population.

Vaccines still make a difference

Despite the fact that both Hong KongAnd New ZealandBoth countries have seen a dramatic rise in viral transmission in recent years, but the impact on public health has been quite different.

New Zealand is faring much better than the rest, thanks to its high vaccination coverage and recent booster programme. Hong Kong has seen many more deaths, with a death rate per million people in the four weeks up to March 18 2022 that’s 38 times as greatAs in New Zealand.

This is due to the differences in vaccination campaigns. The uptake of the booster vaccination in Hong Kong was lower than in New Zealand at least until February 31, and it was especially low in Hong Kong. older, more vulnerable age groups. Even second-dose coverage was not high in these groups, so many were at high risk for severe disease and death.

Did the UK do it right?

My country, the UK decided to lift its remaining restrictions earlier in this year, even though there were still many cases when controls were eased. This was the right decision.

There’s no right answer, but given that non-pharmaceutical control measures only delay infections rather than prevent them, such measures should only continue if the benefits of delaying infections outweigh the more general harms to society and human health that come with restricting people’s freedoms. Because of the high number of cases and good vaccination coverage in Britain, it was sensible to lift control.

There’s also another important point to consider here. It’s been well publicised that the vaccines’ protective effect against catching the virus and developing symptoms wanes more quicklyThere is no protection against severe illness and death. However, there’s emerging evidence(still in preprint, so awaiting review from other scientists) That protection against severe diseases also wanes with time.

This means that people who delay getting sick could end up getting COVID later, when they are more likely to become seriously ill. This was predicted in some studies. disease modelling of omicronPublished at the end of last calendar year (also still in print). Additional restrictions in December 2021 would have decreased COVID deaths in January 2022 but at the expense of more deaths in March.

Personally, I would rather wait until March 31st to lift restrictions. That way we could get into spring, when respiratory illnesses spread less quickly. This would have helped to reduce the NHS’s current pressures due to staff absences.

Finally, even though lifting restrictions was logical, the UK still has a large population of older people or those who are clinically vulnerable to the virus. Their vaccine immunity is decreasing and they have not yet been infected. We must focus now on preventing these people from developing severe disease – perhaps through further vaccine boosters or use of antiviral drugs – rather than on attempting to reduce transmission in the general population.

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