What is genomic sequencing and how significant is Ghana's first genomic sequencing of Covid-19 to public health?

Covid-19, though no longer a public health emergency of international concern, it is still an ongoing health problem. One good public health tool that helped to combat Covid-19 was genomic sequencing. Just less than a month after Ghana's first Covid-19 cases, Scientists from two research institutes, the Noguchi Memorial Institute for Medical Research and the West African Centre for Cell Biology of Infectious Pathogens, collaborated to analyse the virus's genetic sequence using genomic sequencing technology. The feat was very important. It gave hope and impetus to the fight against Covid-19 at the time and that made the majority of Ghanaians proud of our expertise. But what is genomic sequencing? How important is Ghana’s first genomic sequencing of Covid-19 to public health and disease prevention? Here, understanding the nature of DNA (Deoxyribonucleic Acid) helps to appreciate genomic sequencing.

The discovery of DNA by Watson and Crick in 1953 was a huge milestone in Molecular Biology. Since then, studying DNA has continued to revolutionise healthcare, forensics, and bioengineering. DNA is the genetic code for all life forms. Every life form has unique DNA, making it a key focus in genetic studies. DNA contains genetic information that is passed down from one generation to the next. Due to DNA scientists can now explore and manipulate an organism at an advanced level called the molecular level. Scientific fields, including Molecular Biology, Microbiology and Biochemistry owe their relevance to DNA. The studies and understanding of DNA birthed genomic sequencing. The knowledge about DNA sequencing has dramatically improved the evolutionary classification of organisms.

The DNA sequence is key in evolutionary classification. The order of DNA bases depicts the sequences and assigns them as A (adenine), C (cytosine), G (guanine) and T (thymine). The PCR (polymerase chain reaction) technique makes it easier to sequence DNA of an organism by amplifying a single gene into millions of copies. You remember the often used acronym PCR during the height of Covid-19 testing, don´t you? Amplifying the genes of an organism into millions of copies by PCR gives scientists the luxury to study the organism in detail. Relatively, it is easy to sequence a gene once it is amplified. Once the DNA sequences of organisms are known, scientists can use molecular phylogenetics to study how species are related and evolved. Phylogenetics compares molecules of organisms to see how similar they are at the molecular level. The higher the similarity of the molecules, the higher the relatedness of the species. This approach is what is used to determine the variants of disease-causing agents as they evolve and cause diseases. The approach permits scientists to study processes inside cells and compare their similarities at the molecular level and not just observe physical characteristics visible to the naked eye or through a microscope. Therefore, Genomic sequencing in public health is a lab procedure that determines the DNA makeup of a disease-causing organism. It helps us understand, prevent, and treat diseases by monitoring changes in the genome of the microorganism.

Importance of genomic sequencing

1. Genomic sequencing provides immediate and valuable information about circulating variants of Covid-19 to scientists. The information obtained from genomic sequencing is used by scientists to characterise a virus or a pathogen, estimate its prevalence in the population, its spread/outbreaks and evaluate how effective medical treatments are against it. Scientists can gather these sequences and analyse their similarities and differences in a process known as genomic surveillance. Through genomic surveillance, scientists are able to track the spread of variants, monitor changes to the DNA or genetic code of Covid-19 variants thereby helping to better understand how these variants impact public health. For example, the part of the Covid-19 virus called the spike protein is used by the virus to attach to human cells during infection, this is a disease-causing feature of the virus. Any changes to this part of the virus can affect how easily the virus spreads and how effective vaccines are against it. By genomic sequencing, Scientists can therefore monitor this part of the virus closely to inform and protect the public's health.
2. Genomic sequencing technology provides a major boost to explore the scalability to tackle a wider range of infectious diseases. This capability can be used to enhance monitoring and control of other pathogens that have bedevilled us for years. In the democratic republic of Congo, scientists in collaboration with the ministry of health had begun applying genomic sequencing capacities developed to combat Covid-19 to other pathogens, including those responsible for malaria, tuberculosis and gastrointestinal diseases in children. African countries including South Africa, Morocco and Senegal are already exploring and applying genomic sequencing to combat various diseases.
3. The technology can also be used to develop genomic screening for newborns. This helps detect genetic and metabolic disorders early, such as diabetes, heart diseases, sickle cell anaemia, just to mention but a few. Genomic screening of newborns for instance, will ensure that proactive steps are taken to help children get the support and personalised care they need to thrive.
4. Genomic sequencing can be used in the fight against antibiotic resistance which is considered as one of the greatest global public health threats today. For example, a genomic sequencing protocol can be established to describe the genes of antibiotic resistant bacteria thereby making it possible to adapt treatment measures to better manage patients.
5. Genomic sequencing provides more accurate results corresponding to the exact disease situation in the country. What it means is that, scientists in Ghana can now describe and analyse the situation right here at home, without extrapolating from what is happening elsewhere. Therefore, policymakers are better informed in real time.
6. Furthermore, genomic sequencing capabilities can help strengthen our national capacities around clinical trials which will give us the impetus to introduce new treatments and vaccines against Covid-19 and other diseases.
7. Also, genomic sequencing can provide information to help policymakers to understand the circulation of variants in the country, to adapt response measures according to their infectivity, and to anticipate the next wave of infections. With the knowledge of circulating variants, genomic sequencing permits for a precise response thereby optimising the use of our constrained resources. For example, in most countries, during the peak waves of the Covid-19 pandemic, the more lethal variant, the delta and the more contagious variant, the omicron were brought under control by public health response activities targeted at the hospitals (to optimise patient care) and communities (outreaches) respectively, thanks to genomic sequencing. Genomic sequencing is an essential public health tool that must be harnessed to the fullest for the greater good in this country.

What we should be doing as a country
During an epidemic or pandemic, robust public health labs are crucial for a resilient healthcare system. The use of genomic sequencing in Ghana shows the need for research and trained scientists to fight diseases and unexpected public health challenges. The government should strengthen genomic sequencing in our various public health laboratories to empower the country in terms of disease surveillance and patient care. We should regularly bring equipment up to standard, invest in personnel training to optimise use of the equipment and make available reagents necessary for genomic sequencing in our various research centres and public health labs. We should also strengthen existing collaborations and not be over reliant on our external/donor partners, and be focused on improving our local expertise for sustainable public health response systems.

Despite its unexpected ravages, Covid-19 has exposed our weaknesses as well as our strengths in terms of health emergency preparedness and response. As much as it is important to improve on our strengths, it is also very imperative to quickly deal with our weaknesses and be more prepared for future crises. That is what other countries are doing and are moving on stronger and well prepared than before.

To conclude, it is important to note that the geopolitics of global public health today has always left Africa behind. Africa has observed with great disappointment the hoarding and selective delivery of vaccines by rich nations during the Covid-19 crisis. Of the total number of global vaccines produced against Covid-19, only 3% was delivered to Africa, a continent with close to 1.5 billion of the world's population. The inequalities and disparities in the global health community were therefore very clear when Covid-19 struck, and Africa was left furthest behind. As a country, we need to urgently learn important lessons from the experience. This is the time to build resilient public health emergency and response systems to be more self-reliant and self-sustaining in times of epidemics and pandemics; and genomic sequencing should be the solid foundation moving forward.

Authored by: Niadawe Ismael Issaka
Reference
https://www.afro.who.int/news/scaling-genomic-sequencing-africa.