Delta transmission prompts experts to rethink concept of herd immunity

The last week has brought so many ‘new dramas’ to Portugal’s door that it would have taken the most miserable pessimist to predict them.

Only seven days ago the country heard from its prime minister that spiralling numbers of new infections prompted by rapid spread of the Delta variant had taken the country’s combat of Covid-19 into dangerous territory. We were ‘losing control’ of transmission, he warned.

At the same time, Angela Merkel gave signs that Germany was not best pleased with Portugal’s decision mid-May to open its doors to (infected) Britons (notwithstanding that no-one knew they were infected at the time…)

What no-one could predict as the country stepped away from six months at the head of the rotating Council of the European Union was what happened next.

Hours after European Commission president Ursula von der Leyen showered praise on Portugal’s PM António Costa – citing his ‘success’ in rolling out the Covid Digital Certificate designed to allow European citizens the chance of ‘free mobility’ through the summer – Germany fired a broadside.

No matter whether people were double-jabbed with an approved vaccine, recovered from Covid infection or PCR test negative, Germany ‘didn’t want them’.

By red-listing Portugal as a travel destination late on Friday afternoon, Germany effectively gave its citizens on holiday here little more than 72 hours to get back home, or face 14 days’ quarantine.

For the battered tourism sector that has already lost its principal tourist market (the UK), this was and remains “a drama”.

Hotels that had just started ‘breathing a little’ with the influx of German visitors saw people checking out en-masse.

“Millions of euros in cancellations” have followed.

Germany’s decision is ostensibly only valid until July 13 when the German government will ‘think again’. But it has been enough to dash the hopes of a sector already close to desperation.

“Things will get worse before they get better,” health minister Marta Temido has admitted in a television interview that added to the surreal quality of the week.

Ms Temido was not talking to a news anchor at prime time: she was talking to an afternoon chat show hostess, who asked her questions like “have you ever thought of resigning…”

It may have been a way of trying to somehow ‘soften’ the drama.

Ms Temido intimated that Covid vaccines will “very probably” be included in national vaccination programme “as is the case of measles”, which was further indication that the pandemic programme which set out to ‘protect the most vulnerable’ has now morphed into a strategy to inoculate even those who initially were believed unlikely to suffer the most adverse effects of this new coronavirus.

Somewhere in the middle of all these pivotal policy changes, Portugal suddenly announced that no Britons would be welcomed into Portugal without proof that they had been double-jabbed at least 14 days prior to flying.

This caused a manic 24 hours in which fully-vaccinated parents (many of them Portuguese emigrés, desperate for a holiday back home) tried to discover whether the policy excluded children (who can’t yet get the vaccine as the vaccinations haven’t been approved for them).

It does – for the time being at least, as long as they are under-18.

Thus, Portugal sits nervously in the eye of a storm of forever changing rules and regulations.

Tourism bosses fear Germany’s red listing will see other markets follow (click here). Brussels is attempting to change Germany’s mind – valiantly waving the Covid Digital Certificate with the question: “What was this all for if not to elicit confidence?” and experts are warning: “We need to rethink our way out of this” (click here).

Pre-Delta scientific belief was that countries would be safe with roughly three-quarters of their populations vaccinated. Indeed, Portugal’s focus has always been on ‘herd immunity’ being attainable with 70% covered (which seemed to be likely by the end of the first week of August). Now, all that has changed.

Thinking (this week) is that at least 85% of the population will need to be fully-vaccinated in order to reach the nirvana of herd immunity.

Intensive medicine specialist José Artur Paiva has also stressed that even so, measures to reduce transmission (masks, distancing, hand washing) will need to remain in place, while investigator Miguel Castanho of the University of Lisbon’s Institute of Molecular Medicine explains why.

In his opinion, the notion of herd immunity has been compromised by the fact that “vaccines are not 100% efficient”.

They “do not protect against infection or against the capacity for transmission, meaning any person, even vaccinated, to some degree contributes to transmission of the virus”.

The only way true herd immunity can be attained is “when a series of people cannot be infected and cannot transmit the virus to other people”, he told Expresso.
And that, for the time being, looks impossible.

Thus, to a large extent, Germany’s decision has been explained. But the future is all the more confusing.

The experts’ consensus, backed by governments, is that ‘vaccination programmes must be continued and stepped up apace’ as the full complement of shots protect against hospitalisations and the likelihood of death.

To that end, Portugal’s is going as fast as it possibly can, aiming at inoculations of roughly 90,000 per day through July (click here).

But there are still no guarantees.

And while Europe is still tying itself up in a Gordian knot of travel rules and regulations, countries elsewhere like Singapore have decided it’s time to start thinking of treating Covid “like other endemic diseases, such as flu”.

Singapore’s experience with Covid-19 has been light years (in the right direction) away from Portugal’s and the rest of Europe, but its decision is interesting because, like health minister Marta Temido’s reference to measles, Singaporean authorities have referred to treating the virus “like influenza or chickenpox”.

Again, the key, they say, will be in getting as many people vaccinated, and then doing away with goals of zero transmission, quarantine and daily Covid bulletins.

But it’s still a long way off – and that’s in Singapore which has only lost a few hundred people to Covid since the start of the pandemic.

Portugal is still trudging through the mire, and every week seems to become a little more bogged down with conflicting information.

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