Thursday, April 15

The global launch of vaccines is no longer a guarantee of victory over Covid-19 | Coronavirus


TOBy the end of 2020, there was great hope that high vaccination levels would see humanity finally win the hand over Sars-CoV-2, the virus that causes Covid-19. In an ideal scenario, the virus would be contained at very low levels without further social disruption or a significant number of deaths.

But since then, new “variants of concern“They have emerged and spread throughout the world, putting current pandemic control efforts at risk of derailing, including vaccination.

Simply put, the game has changed and a successful global launch of the current vaccines alone is no longer a guarantee of victory.

No one is really safe from Covid-19 until everyone is safe. We are in a race against time to keep global transmission rates low enough to prevent the emergence and spread of new variants. The danger is that variants will emerge that can overcome the immunity conferred by previous vaccinations or infections.

Furthermore, many countries lack the capacity to track emerging variants through genomic surveillance. This means that the situation may be even more serious than it appears.

As members of the Lancet Covid-19 Commission Working Group on Public Health, We call for urgent action in response to new variants. These new variants mean that we cannot rely on vaccines alone to provide protection, but must maintain strong public health measures to reduce the risk of these variants. At the same time, we must accelerate the vaccine program in all countries equitably.

Together, these strategies will offer “maximum suppression” of the virus.

What are ‘variants of concern’?

Genetic mutations of viruses such as Sars-CoV-2 arise frequently, but some variants are labeled “variants of concern“, Because they can re-infect people who have had a previous infection or vaccination, or who are more transmissible or it can lead to more serious disease.

There are currently at least three documented Sars-CoV-2 variants of concern:

  • B.1.351, first reported in South Africa in December 2020

  • B.1.1.7, first reported in the UK in December 2020

  • P.1, first identified in Japan among travelers from Brazil in January 2021

Similar mutations are emerging in different countries simultaneously, meaning that even border controls and high vaccination rates cannot necessarily protect countries from local variants, including variants of concern, where there is substantial community transmission.

If there are high levels of transmission and thus extensive replication of Sars-CoV-2, anywhere in the world, more variants of concern will inevitably arise and the more infectious variants will dominate. With international mobility, these variants will spread.

The South African experience suggests that past infection with Sars-CoV-2 offers only partial protection against variant B.1.351, and it is about 50% more transmittable than pre-existing variants. Variant B.1.351 has already been detected in at least 48 countries as of March 2021.

The impact of the new variants on the effectiveness of vaccines is not yet clear. Recent real world evidence from the UK suggests that both Pfizer and AstraZeneca vaccines provide significant protection against severe illness and hospitalizations of variant B.1.1.7.

On the other hand, variant B.1.351 seems reduce efficiency of the AstraZeneca vaccine against mild to moderate disease. We don’t yet have clear evidence on whether it also reduces effectiveness against severe disease.

For these reasons, reducing community transmission is vital. No action is sufficient to prevent the spread of the virus; we must maintain strong public health measures along with vaccination programs in all countries.

Why we need maximum suppression

Every time the virus replicates, there is the possibility of a mutation. And as we are already seeing around the world, some of the resulting variants risk eroding the efficacy of vaccines.

That’s why we have called for an overall “maximum suppression” strategy.

Public health leaders should focus on efforts that suppress viral infection rates as much as possible, thereby helping to prevent the emergence of mutations that may become new variants of concern.

Rapid vaccine launches alone will not be enough to accomplish this; Ongoing public health measures, such as face masks and physical distancing, will also be vital. Ventilation of interior spaces is important, some of which are under people’s control, some of which will require adjustments in buildings.

Fair access to vaccines

Global equity in access to vaccines it is also vital. High-income countries should support multilateral mechanisms such as the Covax facility, donate excess vaccines to low- and middle-income countries, and support increased vaccine production.

However, to prevent the emergence of worrisome viral variants, it may be necessary to prioritize countries or regions with the highest levels of disease prevalence and transmission, where the risk of such variants emerging is greatest.

Those with control over health care resources, services, and systems should ensure that support is available for health professionals to manage increased hospitalizations for shorter periods during overloads without reducing care for patients who do not have Covid-19.

Health systems must be better prepared against future variants. Law enforcement efforts must be accompanied by:

  • Genomic surveillance programs to rapidly identify and characterize emerging variants in as many countries as possible around the world.

  • Rapid, large-scale “second generation” vaccine programs and increased production capacity that can support equity in vaccine distribution.

  • Vaccine efficacy studies in existing and new variants of interest

  • adapt public health measures (such as double masking) and re-commit to health system arrangements (such as ensuring personal protective equipment for health personnel)

  • behavioral, environmental, social and systems interventions, such as allowing ventilation, distancing between people and an effective search, testing, tracking, isolation and support system.

Worrisome variants of Covid-19 have changed the game. We need to recognize and act on this if we, as a global society, are to avoid future waves of infections, even more lockdowns and restrictions, and preventable disease and death.

This article was first published in The Conversation. It is republished here under a Creative Commons license.

  • By Susan Michie, Chris Bullen, Jeffrey V Lazarus, John N Lavis, John Thwaites, Liam Smith, Salim Abdool Karim, and Yanis Ben Amor

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