Questions concerning COVID-19 testing and changes to vaccine dose schedule: FOI release

Information request and response under the Freedom of Information (Scotland) Act 2002.

Information requested

1. Could you please provide evidence that the delaying of the second Pfizer vaccine does not affect the efficiacy.

2. Could you please explain why the Governments are recording Covid Deaths as anyone having tested positive with covid by PCR testing.

3. Could you please provide information on what PCR cycles are being used in your labs to verify Covid

4. Could you please let me know what is being done by the Government to investigate the safe use of alternative treatments such as Ivermectin.


1. The change in dose schedule only applies to the Pfizer BioNTech vaccine. It was originally licensed by the regulatory body in the UK (the Medicines and Healthcare Regulatory Authority - MHRA) on the basis that the second dose would be administered 21 days after the first dose. This was based on the data presented (and published publicly) to them from Pfizer from stage 3 of the clinical trial.

However, the MHRA subsequently had access to other data from Pfizer (not publicised from the manufacturer) which indicated a very high level of efficacy between the first and second dose that was longer than 21 days (up to 12 weeks). The MHRA subsequently revised the conditions of their approval enabling the vaccine to be used with a longer dose interval.

However, how vaccines are used are guided by the Joint committee for Vaccination and Immunisation (JCVI) and they met also reviewing all of the available evidence and concluded the dose schedule between 1st and 2nd doses for both the Pfizer and AstraZeneca Vaccine (which at that time was just about to be approved by the MHRA) should be up to 12 weeks given both demonstrated a high level of efficacy. The 4 CMOs also met to consider this advice and concluded that they were in full support of this approach. All have published their conclusions separately (MHRA, JCVI and 4 CMOs).

All Governments in the UK have agreed to be bound by the independent clinical advice of the JCVI and why from the 4 January, the change in dose schedule was applied to the Pfizer vaccine and anyone receiving the newly approved AstraZeneca vaccine.

This approach has enabled all nations to provide a first dose of the vaccine to more people than we would have with a shorter dose schedule and importantly is informed by independent clinical advice.

2. The certification of a person’s death is a matter that falls within the clinical responsibility of medical practitioners, who require to be satisfied, on the balance of probabilities, as to the likely cause of death. Medical practitioners are aware that the Medical Certificate of Cause of Death (MCCD) is a legal document and information included in such a document must be to the best of their knowledge and belief.

We recognise the importance of high-quality, accurate completion of the MCCD and we have issued comprehensive Guidance for Doctors Completing Medical Certificates of Cause of Death (MCCD) and its Quality Assurance. Also available to doctors is a wide range of educational resources. Scotland's Chief Medical Officer (CMO), jointly with Police Scotland, Crown Office and Procurator Fiscal Service (COPFS) and National Records of Scotland (NRS) also issued guidance to doctors for death certification during the COVID-19 pandemic.

When doctors complete a MCCD they are advised to consider a range of factors in order to determine whether, on balance, “COVID-19 Disease” or “presumed COVID-19 disease” can legitimately be recorded as the cause of death. These factors include, but are not limited to:

  • Presence of COVID-19 symptoms

  • Reports of symptoms from family and friends

The wider facts and circumstances surrounding the death such as: that COVID-19 pandemic had struck in the locality; or evidence of medication suitable for treating the symptoms of a COVID-19 found in or near the deceased’s possessions. Whether a certifying doctor records influenza or COVID-19 on a MCCD, is a matter of clinical judgement.

A person who has questions or concerns about the content of the MCCD, after speaking to the doctor, can consider applying to the Death Certification Review Service (DCRS) for an ‘Interested Person Review’. More information on what an Interested Person Review is and who can apply is available here.

3. Each manufacturer of the RT-PCR test will recommend a differing maximum amplification cycle number when determining the presence of SARS CoV-2, but a maximum of around 40 amplification cycles is typically recommended by test manufacturers. Information on PCR cycles can be found here:

HPS Website - COVID-19 - laboratory testing frequently asked questions (

Neither the Scottish Government, nor its national public health board, Public Health Scotland holds information on the individual threshold used for every RT-PCR test in use, as the validation and interpretation of the test results are carried out by the individual laboratory performing the test.

4. It may be helpful if I explain that the Medicines and Healthcare products Regulatory Agency (MHRA) is the UK agency responsible for the approval of clinical trials in the UK and of marketing authorisations (licences) for new medicinal products. I have contacted the MHRA, who have provided the following information:

The MHRA is aware that ivermectin, administered orally, is being studied for safety and efficacy in numerous clinical trials worldwide. This includes an exploratory study being conducted within the UK: Exploratory Ph I Trial of the Active IMP in Healthy Volunteers in Relation to COVID-19 - Full Text View -

MHRA would welcome further applications for clinical trials to be conducted within the UK and are able to offer an expedited review for COVID-19 related clinical trials.

It should be noted that WHO do not generally directly conduct clinical trials themselves and therefore there is a reliance on other companies or organisations taking on the role of Sponsor for a clinical trial. For further information on global clinical trials with ivermectin, please refer to the following website: Home -

For ivermectin to be granted a licence for COVID-19, an application must be submitted to the MHRA for review. The grant of a licence is different from the policy of using the product in clinical practice. At this time, no application has been received for a marketing authorisation containing ivermectin for use in COVID-19, in the UK, however should an application for a marketing authorisation be made for an ivermectin containing medicine, then the MHRA has processes in place to expedite such an application, as required.

The MHRA together with independent advisory groups, continues to review the emerging body of evidence regarding potential medicines for treatment or prevention of COVID-19.

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