Tue. Oct 19th, 2021

Genomics Update

The author, a Nobel laureate in physiology or medicine, is chairman of the WHO Science Council

The rapid spread of the Delta variant of Sars-Cov-2 has sparked hopes that the pandemic may soon be over. It also predicted that even more dangerous variants, including those that are impervious to vaccines or previous infections, could arise.

We do not have complete knowledge of how the most dangerous variants of Sars-Cov-2 are generated, but we do know that it is emerging by mutations to the genome which occurs when the virus is repeated. Such mutations are more likely to occur in immunocompromised individuals in whom the virus may recur for long periods of time. Special concerns are those that infect cells more efficiently or evade immune response.

As long as the virus is spreading as widely as it is now- especially in unaffected populations found in rich countries with large vaccines and in low- and middle-income countries where vaccines are very limited- a significant proportion of infected individuals should be monitored for viral variants. This cannot be done with the two widely available tests – by means of the polymerase chain reaction or an antibody test – as these tests are not designed to detect mutations. Genome sequencing, performed by machines that can quickly read the sequence of the four chemical elements that make up viral genomes, should be used to identify mutations, followed by studies to determine if it is responsible for changes in the behavior of the virus.

The consequences of mutations can be severe, but it is difficult to predict only from the genomic sequence and must be deduced. For example, if a variant occurs more and more frequently among individuals in one area, it implies a higher infectivity, while worse diseases imply a greater pathogenicity. Infection of vaccines and unvaccinated at similar doses means that it can evade immune responses – a particularly worrying development.

To uncover such critical information, it is essential to follow up viral genomes of infected individuals, wherever the virus spreads; to correlate genome order with vaccination status, clinical findings, and health outcomes; and to share the information efficiently, openly and fairly.

Earlier this year, a new Science Council was convened by the World Health Organization to advise on technologies to be used to improve global health. The board, of which I chair, has established us in the broad field of medical genomics as our first long-term goal. The sequencing of human and microbial genomes has recently improved the diagnosis, treatment, and prevention of disease in richer countries, but has been slowly, if at all, adopted in low- and middle-income countries.

It is not easy to ensure the responsible practice of genomics in all parts of the world – including countries with little technology or trained staff and dysfunctional management – and it requires international help from various sources. The WHO cannot afford to do the technical work alone. Relatively wealthy countries and well-equipped foundations must act, either out of generosity or out of self-interest, to expand genomics and exchange information. There are strong precedents for such actions, for example the President’s Emergency Relief Plan allowed the US to stop the devastating passage of HIV / Aids in very poor countries, especially in Africa.

The benefits of such investments will not be limited to Sars-Cov-2. The establishment of a technological ‘beach head’ could be a prelude to the continued growth of genomic capabilities that improve medical care and public health more generally. It can promote research in many fields, such as in agricultural productivity, and give other enterprises, such as biotechnology, economic and cultural value. In this way, the pandemic can become more than a crisis: it is an opportunity to promote world health.

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