Tuesday, May 11, 2021

Vaccines have been oversold as an exit strategy from the pandemic

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The writer is a science commentator

Logistics permitting, around 15 million people in the UK will have received at least one dose of a Covid-19 vaccine by some time in February. Provided that the second doses are given in a timely manner, this should prevent the most vulnerable from reaching the hospital.

This milestone will not push us much further towards normality, however. We do not yet know if vaccines slow transmission, although it is reasonable to hope that they could. Most people of working age are unlikely to receive a first dose before summer. While older people can savor a newfound freedom, it’s unclear why unprotected people should be expected to return to non-essential workplaces, especially amid concerns over a more deadly variant. Since vaccines have been sold As the main exit strategy arrives in the spring, serious management of expectations is now required – with a constant focus on removing the virus.

One source of gloom emerged during a briefing last week. University researchers warned vaccination only may not induce sufficient collective immunity to eradicate the virus. An unfortunate combination of imperfect vaccine efficacy, optimal underuse, and super-infectious variants could derail attempts to reach the herd immunity threshold, when R drops below one and the virus begins to self-destruct. dispel. Modeling of the University of East Anglia corroborates this unpleasant possibility.

Another major concern is that countries with poorly controlled transmission could act as production lines for dangerous new variants. While current vaccines work against high-level variants, including B.1.1.7, now dominant in the UK, that chance may not last.

A variant, first documented in South Africa, shows some laboratory resistance to neutralizing antibodies, scientists in an unexamined research paper last week. Moderna also said his vaccine might not be as effective against this variant and started to develop a new formulation which could be given as a reminder in the fall.

The key genetic mutation responsible has also been clocked in a Brazilian variant. Yet another has been linked to a surge in california, where 3 million cases have been recorded.

Researchers have already suggested that immunocompromised patients who suffer from long infections could act as Petri dishes for these irrepressible strains. But there may be a plausible alternative hypothesis, according to Tulio de Oliveira, a bioinformatician at the University of KwaZulu-Natal. He co-authored the article on the South African variant and contributes to the World Health Organization virus evolution working group. His opinion led British scientists to investigate in more detail variant B.1.1.7.

“We recently had an open discussion in the group about why these variants emerged independently in so many places,” says Professor de Oliveira. “We noticed a common factor about London, the Eastern Cape [South Africa] and Manaus [Brazil], where these three variants appeared: they were very strongly affected during the first wave of infection.

This first wave, it is hypothesized, produced many people with antibodies which then gradually declined over time. In the second wave, some previously infected people who regained the virus did not have strong enough immunity to prevent reinfection or kill the virus quickly. Indeed, according to Professor de Oliveira, a person with diminished natural immunity can play the same role as an immunocompromised patient.

If areas where transmission is raging serve as breeding grounds for resistant variants, failure to control the spread will prolong the pandemic. Professor de Oliveira points out that Taiwan, China, Australia and New Zealand, which have chased elimination, are the models to follow. “It should be a wake-up call for all of us to control transmission, not only in our own regions, but globally. This virus will continue to outsmart us if we don’t take it very seriously, ”he says.

This means not only vaccination, but also rapid testing, accurate and rapid contact tracing, quarantine and isolation. In short, vaccination should go hand in hand with removing the virus and not becoming a substitute for it. A successful deployment of the vaccine will count for little if the country then becomes a melting pot of resistant variants.

Over the past year, we’ve given the virus several inches and it has taken a lot of miles. Even mild infections can lead to “long Covid», Characterized by fatigue and shortness of breath that persist for months. The pandemic is also creating a secondary epidemic of trauma among survivors and caregivers. Countries where transmission is endemic face a chronic health burden, both physical and mental, for decades to come.

Excellent vaccines, thankfully, reach millions of guns, but removal remains a crucial part of the final phase.

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