In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

The Prophet [peace and blessings of Allaah be upon him] said, “الْمُسْتَشَارُ مُؤْتَمَنٌ – The consultee is in a position of trust”. (1)

[المستشار -The Consultee]: He is the one whose opinion is sought regarding an affair of Maslahah [i.e. an affair that will bring about benefit and repel harm]. He is in a position of trust with regards to what he is asked and it is not permissible for him to deceive the one who consults him by concealing the affair that would bring about benefit. (2)
The Muslim doctor should not make the patient a means of experimenting the effectiveness of a medication, especially if he fears that there would be severe side effects, because this experimentation would negate the honour Allaah has bestowed on the children of Aadam. Allaah [The Most High] said:

[وَلَقَدۡ كَرَّمۡنَا بَنِىٓ ءَادَمَ وَحَمَلۡنَـٰهُمۡ فِى ٱلۡبَرِّ وَٱلۡبَحۡرِ وَرَزَقۡنَـٰهُم مِّنَ ٱلطَّيِّبَـٰتِ وَفَضَّلۡنَـٰهُمۡ عَلَىٰ ڪَثِيرٍ۬ مِّمَّنۡ خَلَقۡنَا تَفۡضِيلاً۬ – And indeed We have honoured the Children of Adam, and We have carried them on land and sea, and have provided them with At-Taiyibat(lawful good things), and have preferred them above many of those whom We have created with a marked preference]. [Surah Al-Is’raa Aayah 70]

This deed [i.e. using the patient as a means to experimenting the effectiveness of a medication] negates the command given to person to safeguard the blood of a Muslim. The Prophet [peace and blessings of Allaah be upon him] said, “A Muslim is the brother of another Muslim, so he should not oppress him, nor should he hand him over to an oppressor. Whoever fulfilled the needs of his brother, Allaah will fulfil his needs; whoever brought his [Muslim] brother out of discomfort, Allaah will bring him out of a discomfort from the discomforts of the Day of Resurrection, and whoever screened a Muslim, Allaah will screen him on the Day of Resurrection”. (3)

The affairs of medicine attributed to the Prophet [peace and blessings of Allaah be upon him] should be checked as to whether their chains of transmission are authentic, and the affairs of medicine that are established by way of opinions [i.e. through study and research etc] should be examined to find out whether they are (sound, unsound, or whether they contain flaws, sin, offence etc). He should not be an easy and legitimate prey whom the enemies of Allaah use as a means to transmit that which opposes the Religion of Islaam and causes harm to the Muslims; rather he should know that everything that comes to him regarding modern medicine has to be subjected to research and has to be ascertained. [Excerpt from Akhlaaq At-Tabeeb Al-Muslim pages 4- 18]

Recent development: What is this Saudi Cardiologist saying about the vaccine?

Finally, read “An Advice Regarding Differing Over COVID-19 ― And Understanding The Ijitihād Of Scholars In Worldly Affairs”- By Shaikh Abu Khadeejah [may Allaah preserve him]: https://abukhadeejah.com/advice-regarding-differing-over-covid-19/

[1: Reported by Abu Dawud Number 5128’ & declared Saheeh by Imaam Albaani (rahimahullaah) in his checking of Sunan Abee Dawud]
[Ref 2: See Hadeeth Number 5062′ Vol 4’ page 259′ in Mirqaat Al-Mafaateeh Sharh Mishkaat Al-Masaabeeh]
[Ref 3: Bukhaari Hadeeth Number 2442]