Dr Musa Mohd Nordin, Paediatrician
17 July 2021
One of the reasons attributed to the exponential rise in the cases, hospitalisations and deaths is the presence of the Variants of Concern (VOC) in the community. [1]
It has been shown that these VOC are more transmissible, hence the rising numbers and that the infections are more severe, leading to more hospitalisations and mortalities. [2]
This Canadian study has shown that the Beta variant (South Africa B.1.351) is responsible for a 59% increase in hospitalisation, 105% for ICU admission and 61% increase in mortality compared to the non-VOC strains. [3]
Even higher increases were seen with the Delta variant (India B.1.617.2) They caused a 120%, 287% and 137% increase in hospitalisation, ICU admission and mortality respectively.
The table I below illustrate the presence of the VOC in Malaysia up until 13 July 2021.
109 (37%) of the VOC were detected in the Klang Valley, Labuan and Negeri Sembilan. It consisted of 61 Beta variants, 37 Delta variants, 8 Alpha variants and 3 others.
The Mutation Report showed that in the early days of genomic sequencing the major variant detected was Beta (39%). However Beta have since been overtaken by Delta. The prevalence of VOC in Malaysia in the previous 60 days was Delta (36%) and Beta (34%). And over the previous 30 days the Delta variant constituted 72% of the variants isolated. [4]
Real world experience showed that the vaccines studied showed good effectiveness against the VOC, especially against severe COVID disease.
The Table II below summarises the protection conferred by the vaccines against the various VOC.
Table II: The Vaccine Efficacy against the various Variants of Concern
Real world studies from the UK and Canada showed that 2 doses of the Pfizer vaccine were 88% and 87% effective respectively at preventing symptomatic infection by the Delta variant. This would have the effect of reducing transmission and the further spread of the Delta variant. [5]
Taking into account the estimated prevalence of the VOC in the Klang Valley, NS and Labuan, and the effectiveness of the available vaccine portfolio, we would like to suggest the following targeted vaccination strategy to mitigate the unpsurge of cases, hospitalisations, ICU admissions and deaths in an effort to protect the presently overwhemed healthcare services.
Table III: The Incidence Rate of COVID-19 by Active Cases
1. Since Labuan, the Klang Valley and Negeri Sembilan (Table III) are now the epicentre of the present upswing of the COVID wave, the vaccine rollout should be prioritised in these areas.
2. Knowing the effectiveness of the Pfizer and AstraZeneca vaccines against the predominant VOC in these areas, they should therefore be the vaccines of choice for residents in these areas.
3. All previous COVID patients should be offered a single dose of either the Pfizer or AstraZeneca vaccines. This hybrid immunity has been shown to boost the neutralising antibodies by 50 times and parallels the effectiveness of 2 Pfizer shots [6]
4. Since the South Africa study has shown the futility of 2 doses AstraZeneca against the Beta variant (though more recent studies from Canada showed better VE against symptomatic Beta/Gamma variants and hospitalisation) the JKJAV should consider offering the vaccinees with the first AstraZeneca dose, the Pfizer vaccine as the second dose. Multiple studies have shown the superiority of this heterologous prime-boost vaccination regime in eliciting a better immune response than the AZ-AZ combination [7,8,9]
5. Every person in these 3 zones who are above 60 years of age, has a co-morbidity, lives in a nursing home and the disabled (including caregivers) should have ready and easy access to the Pfizer and AstraZeneca vaccines.
6. Sinovac has been shown to be effective against the wild Wuhan strain and the Alpha variant. It has however not been shown to be as effective against the more transmissible and lethal VOC. It should therefore be deployed in the other states less affected by the VOC. [10,11]
7. The NPRA should seriously consider conditionally registering the Moderna vaccine which like the other mRNA vaccine has shown good resilience against the VOC. This would better prepare the nation’s vaccine arsenal against the onslaught of upcoming and virulent VOC.
8. The mRNA technology has the capability to tweak the antigens to promptly produce a multi-valent COVID vaccine to combat against the VOC. [16]
9. This targeted vaccination strategy is based on the best available evidence of vaccine resilience against VOC and its presence in the COVID epicentre in the 3 areas.
10. It confers flexibility to the authorities in the face of restricted vaccine supply chain, and address the rare but real adverse effects of blood clots with the AstraZeneca vaccinees in those below 60 years old.
11. We hope it would help to rationalise the distribution of the available vaccines in the country in a more evidence based manner in order to achieve optimal protection of the rakyat in the face of the present predicament.
References:
1. https://theconversation.com/why-new-covid-19-variants-are-on-the-rise-and-spreading-around-the-world-153530
2. https://www.nytimes.com/interactive/2021/04/09/world/europe/europe-coronavirus-variants.html
3. https://www.medrxiv.org/content/10.1101/2021.07.05.21260050v2
4. https://outbreak.info/location-reports?loc=MYS
5. https://www.ft.com/content/5a24d39a-a702-40d2-876d-b12a524dc9a5
6. https://drmusanordin.com/2021/05/27/one-dose-vaccine-protective-after-prior-covid-19-infection/
7. https://www.nejm.org/doi/full/10.1056/nejmoa2102214
8. https://www.nytimes.com/2021/06/24/world/europe/covid-vaccine-mix-and-match-pfizer-moderna.html
9. https://www.reuters.com/world/middle-east/countries-weigh-mix-match-covid-19-vaccines-2021-05-24/
10. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00287-5/fulltext
11. https://www.reuters.com/world/china/are-chinese-covid-19-shots-effective-against-delta-variant-2021-06-29/
12. https://www.nejm.org/doi/full/10.1056/NEJMc2104974
13. https://www.reuters.com/article/us-health-coronavirus-pfizer-brazil-idUSKBN2B02JC
14. https://www.reuters.com/article/us-health-coronavirus-brazil-variant-exc-idUSKBN2AX1NS
15. https://www.medrxiv.org/content/10.1101/2021.06.28.21259420v1.full.pdf
16. https://www.wsj.com/articles/covid-19-vaccines-targeting-multiple-strains-are-in-the-works-11615374007
