[MEDIA RELEASE] Suggest shortening the spacing of AZ vaccine doses from 12 weeks to 8 weeks

(Photo: Mika Baumeister/Unsplash)


By Emeritus Professor Dato’ Dr. Lam Sai Kit 

There is data to suggest that several variants are responsible for the large surge in COVID-19 cases in Malaysia (Refer Links 1 and 2). It is also a known fact that two doses of Pfizer and AZ vaccines offer better protection and preventing hospital admission against the Delta variants (Link 3).

In UK, the country’s most vulnerable are being offered the second dose of AZ vaccine earlier than 12 weeks because of the rising cases of COVID-19 due to Delta variant (Links 5, 6, 7). The country has decided to extend the lockdown by another month because of surging cases due to mainly the Delta variant.

Malaysia should reconsider its spacing of the second dose of AZ vaccine and shorten it from 12 weeks to 8 weeks although the 12-week interval may give a stronger immune response (Link 4). However, earlier protection against the more transmissible and more deadly Delta variant should be considered, especially for the elderly and those with comorbidities. Those vaccinated with Pfizer are not affected since they already have their doses spaced 3 weeks apart.

The country should continue to conduct more sequencing, especially among large clusters, to determine the spread of Delta and other variants such as Alpha (originated from Brazil), Beta (originated from South Africa), etc.


  1. https://www.theedgemarkets.com/article/covid19-malaysia-detects-23-new-variant-cases-sarscov2
  1. https://www.nst.com.my/news/nation/2021/05/688901/more-foreign-covid-19-variants-unearthed-malaysia
  1. https://www.irishtimes.com/news/health/covid-19-vaccines-highly-effective-in-stopping-delta-variant-hospitalisations-1.4593267
  1. https://www.cnbc.com/2021/02/03/delaying-second-astrazeneca-vaccine-dose-does-work-study-shows.html
  1. https://news.sky.com/story/covid-19-gap-between-first-and-second-vaccine-doses-shrinks-to-eight-weeks-for-over-50s-amid-indian-variant-fears-12306599
  1. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/978194/uk-HCP-covid-19-vaccine-astrazeneca-reg174_proposed_14_Apr_2021.pdf
  1. https://www.england.nhs.uk/coronavirus/wp-content/uploads/sites/52/2021/03/C1254-covid-19-vaccination-programme-faqs-on-second-dose-v2.pdf

**All previous posts about COVID-19 here: https://sciencemediacentremalaysia.com/tag/covid-19/

Emeritus Professor Dato’ Dr. Lam Sai Kit is a Senior Fellow, Academy of Sciences Malaysia And Research Consultant, Universiti Malaya.

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