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Covid-19 Delta Variant

Coronavirus disease (COVID-19) is an infectious, flu-like disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) [1]. This respiratory viral disease was first identified in Wuhan, Hubei Province, China at the end of 2019 before the virus immediately spread across the globe causing the World Health Organization (WHO) to declare a global pandemic the following year on March 11, 2020 [2]. Since then, the pandemic has ravaged numerous healthcare systems, crippled global economies, infected millions of people, and has been reported to have killed more than 3.8 million people worldwide [2]. Even with considerable progress in clinical research, SARS-Cov-2 continues to cause disorder across the world with many parts experiencing a second and third wave of the viral outbreak [2]. This has been primarily due to the emergence of mutant variants of the virus with the Delta variant currently being the most aggressive [2].

Similar to other RNA viruses, SARS-CoV-2 is prone to evolve genetically while adapting to its new human host over time [3]. The genetic mutations may emerge as variants differing from the ancestral origin with different characteristics [3]. These adaptive mutations in the virus’ genome are sometimes capable of altering the virus’ pathogenic potential which may significantly affect the virus’ ability to escape the immune system and hinder the vaccine development progress [2].

As of June 22, 2021, there were four SARS-CoV-2 variants identified by WHO as variants of concern (VOCs) based on their impact on public health throughout the world [3]. These included: Alpha (B.1.1.7), which was the first variant of concern identified in the United Kingdom at the end of December 2020; Beta (B.1.351) which was first reported in South Africa in December 2020; Gamma (P.1), reported in Brazil in early January 2021; and Delta (B.1.617.2) which was first reported in India in December 2020 [3].

Initially, the Delta variant was only considered a variant of interest (VOI), however by May 2021, WHO had elevated it to a variant of concern after its rapid spread across the globe [2]. By July 27, 2021, the Centers for Disease Control and Prevention (CDC) had released an updated guidance for urgently increasing vaccination coverage because of the emergence of new data demonstrating the increased transmissibility of the Delta strain which was now reversing what had been a steady decline since January 2021 [4]. This variant was shown to be more infectious and more transmissible even among some vaccinated individuals when compared to other variants of the disease [4].

Presently, the Delta variant accounts for as much as 99% of COVID-19 cases in the United States and has shown a significant increase in hospitalization in some states [5]. Even in the Pacific region, the Delta variant has soundly infiltrated itself into the ongoing pandemic in the Pacific Island such as Fiji, Papua New Guinea, and New Zealand for example [6], [7], [8].

Generally, there are six important points of consideration regarding the Delta variant.

1. Delta variant is very contagious

According to the World Health Organization, the Delta variant is about twice as contagious as the original SARS-CoV-2 [9]. Delta spreads about 50% faster than Alpha, which is about 50% more transmissible than the original strain [5].

2. Delta variant symptoms are the same as the original SARS-CoV-2 strain

While most symptoms such as a mild or moderated respiratory illness are the same as the original strain, disease progression appears to be quicker especially in younger people [10]. Vaccinated individuals are often asymptomatic or have mild symptoms from the Delta variant [10]. Symptoms commonly present as being similar to the common cold such a cough, fever or headache, and usually noticeable loss of smell [10].

3. Delta variant appears to affect unvaccinated people more

As stated by two independent studies from Canada and Scotland, unvaccinated patients who were infected with the Delta variant were more likely to be hospitalized than patients infected with the alpha or the original SARS-CoV-2 [4]. Additionally, it is reported that the majority of hospitalization and death caused by COVID-19 are in unvaccinated people [4].

4. Fully vaccinated people with Delta variant breakthrough infections may spread the virus to others but for a shorter time compared to unvaccinated people

Fully vaccinated people were less likely to get infected with COVID-19 than unvaccinated people [4]. When infected with the delta variant, similar amounts of SARS-CoV-2 genetic material were found in both fully vaccinated people and unvaccinated people, however, the genetic material in vaccinated people may go down faster compared to unvaccinated people [4], [5]. This implies that vaccinated people have a shorter contagious period than unvaccinated people [4].

5. Some communities may suffer more from the Delta variant

It has been purported that communities with lower vaccination rates, especially in rural areas with limited access to care, may be overwhelmed by a Delta variant outbreak [10], [5].

6. Vaccination may be the best protection against the Delta variant

According to WHO, the WHO-approved COVID-19 vaccines are stated to be highly effective at preventing severe illness and death, including the Delta variant [11]. In addition, fully vaccinated people are reported to be less likely to get COVID-19 than unvaccinated people [4].

Even with the spread of vaccine development and the continued efforts of vaccination against the prevention of COVID-19, if the transmission rate is not hampered, experts say local healthcare systems may be overburdened and many people may die [5]. The development of new and existing variants also contribute to putting the development of vaccines at risk adding further weight onto the need for minimising viral transmission and contact between person-to-person [3].

As recommended by WHO, the best course of action would be to prevent or slow transmission by being informed on disease and practicing safe, healthy habits [1]. These can be achieved by staying at least a metre apart from others, wearing a face mask, washing your hands regularly, and getting vaccinated if you decide to [1]. By practicing safe habits and being informed, it may be possible to protect not just yourself, but also your community.



"Coronavirus disease (COVID-19)," World Health Organization, [Online]. Available: [Accessed 13 October 2021].


A. Aleem, A. B. A. Samad and A. K. Slenker, "Emerging Variants of SARS-CoV-2 And Novel Therapeutics Against Coronavirus (COVID-19)," PubMed, 18 July 2021. [Online]. Available: [Accessed 12 October 2021].


M. Cascella, M. Rajnik, A. Aleem, S. C. Dulebohn and R. Di Napoli, "Features, Evaluation, and Treatment of Coronavirus (COVID-19)," PubMed, 30 July 2021. [Online]. Available: [Accessed 12 October 2021].


"Delta Variant: What We Know About the Science," Centers for Disease Control and Prevention, 26 August 2021. [Online]. Available: [Accessed 13 October 2021].


K. Katella, "5 Things To Know About the Delta Variant," Yale Medicine, 14 October 2021. [Online]. Available: [Accessed 15 October 2021].


Reuters, "Fiji's Covid-19 hospital mortuary full, Delta variant fuels record infection," The Times of India, 6 July 2021. [Online]. Available: [Accessed 13 October 2021].


"PNG health authorities concerned with Delta in border region," Radio New Zealand, 2 September 2021. [Online]. Available: [Accessed 15 October 2021].


"New Zealand's COVID cases jump as its battles Delta variant," Reuters, 29 Septermber 2021. [Online]. Available: [Accessed 13 October 2021].


"Minimizing the impact of the Delta variant in the Philippines," World Health Organization, 31 August 2021. [Online]. Available: [Accessed 12 October 2021].


"Delta variant: 8 things you should know about this COVID-19 strain," UC Davis Health, 15 September 2021. [Online]. Available: [Accessed 15 October 2021].


UNICEF, "What you need to know about the Delta variant," UNICEF, 23 September 2021. [Online]. Available: [Accessed 14 October 2021].

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