Prof. Joseph Borg, from the Department of Applied Biomedical Science, Faculty of Health Sciences, jointly with Dr Graziella Zahra, Mater Dei Hospital in charge of the Molecular Diagnostics for Infectious Diseases Laboratory, and in collaboration with the and the National Institutes of Health (NIH) and other esteemed organisations, has published seminal work on COVID-19 in Malta in the American Society for Microbiology - Spectrum. The study sheds light on the intricate web of viral diversity behind the waves of COVID-19 outbreaks, especially in the presence of highly transmissible and immune-evading variants of interest (VOIs) or concern (VOCs).
By examining epidemiological data from Malta, and cross-referencing it with genetic sequences of the virus obtained through the surveillance system led by Mater Dei Hospital and the University of Malta, the research team reconstructed the evolutionary journey and geographical dynamics of SARS-CoV-2 in Malta using advanced phylodynamics modeling.
The results of this comprehensive study reveal that cases associated with prominent variants like B.1.1.7/Alpha, B.1.617.2.X/Delta, and B.1.1.529.X/Omicron VOCs were nine times more prevalent than those linked to the original wildtype variants. Remarkably, Malta maintained low to moderate positivity rates (<10%) throughout the pandemic, thanks to a combination of effective public health interventions.
The study also unveiled a significant finding: the analysis of genomic data demonstrated that Malta experienced multiple introductions of the virus, primarily from Northern European countries, mirroring flight connectivity patterns. Additionally, the research highlighted instances of undetected virus transmission, sometimes lasting for extended periods (median = 102 days) before erupting into larger outbreaks. These larger outbreaks were more readily detected when genomic surveillance was active, underscoring the importance of continuous monitoring.
In essence, this study underscores the critical need for the integration of epidemiological and genomic data, particularly in regions where genomic surveillance may be less robust. By strengthening genomic surveillance in Malta, we can enhance our ability to detect viral introductions early and curtail their expansion within the country, while also guiding public health interventions.
Malta's remarkable success in managing the pandemic, despite its initial challenges and small size in comparison to neighbouring European countries, is attributed to stringent adherence to public health regulations and efficient internal communication. The tight-knit community network in Malta allowed for swift implementation of national-level interventions at the community level.
This research provides valuable evidence of the presence of various SARS-CoV-2 lineages, including wildtype strains, VOCs, and VOIs in Malta. Furthermore, it emphasises the significance of combining epidemiological trends with phylodynamic reconstruction to trace COVID-19 cases, comprehend viral diversity, and decipher the timing and spatial patterns of viral introductions. This knowledge serves as a powerful tool to inform targeted public health interventions, ultimately helping to control the transmission of COVID-19 within the community.
For further information, please contact:
- Dr Graziella Zahra, Mater Dei Hospital Molecular Diagnostics for Infectious Diseases Laboratory – by sending an email
The full text article is available .
