On avoiding infection:
Devotee: It was by chance that I got infected.
Prabhupada: No, no. Not chance. Why did you go where there is cholera case? That is your foolishness. Why did you go there? When there is infectious disease a man is forbidden to go there. You went there without any knowledge and you got infected. Now you are suffering. That’s all. There is no question of chance. That is foolishness. Chance means ignorance. Ignorant people, they do not know this. They perform sinful activities, and [when there is a karmic result] they say “by chance.” There is no question of chance. Krishna says, “kāranaṁ guṇa-saṅgo ‘sya” — there is no chance. (Srila Prabhupada on a morning walk in Nairobi, Kenya, 1 November 1975.)
“Be careful about your health first. This information is not only for you but all my noble sons. I am an old man. I may live or die, it does not matter. But you must live for long time to push on this Krishna Consciousness movement.” –SP letter to Rayarama, 1967
“You ask if children may be taken to ordinary medical doctors. Why not? Of course, we do not always trust that these doctors may be doing the right thing, but what can be done? The governing principle for our activity should be to do what is favourable for pleasing Krishna. So, if your child requires medical attention to be fit for serving Krishna, then it is only practical she should get it.” –SP letter to Lalita Kumar and Jambavati, 1971
Regarding Srila Prabhupada getting vaccinated:
Indradyumna Swami recalls: “In 1995, I was on my way to preach in Mozambique while that country was in the grip of a yellow fever epidemic. I was advised to get vaccinated, but the vaccination sounded scary. Being uncertain, I consulted my godbrother, Pusta Krishna Das (Paul Dossick, MD, FACS), who had been Srila Prabhupada’s personal secretary in South Africa. I asked Pusta Krishna Das if Srila Prabhupada had ever gotten vaccinated against yellow fever in order to preach in Africa. Pusta Krishna Das confirmed that Prabhupada had. So I did too. Pusta Krishna Das also mentioned that Prabhupada had gotten vaccinated against the flu on several occasions.”
Regarding testing on animals:
Even Ayurveda depends on intense testing on animals. Here is an excerpt from a morning walk with Srila Prabhupada on June 27, 1976, in New Vrindaban:
“Prabhupāda: Yes. Yes. Āyurveda. There is a book, Dravya–guṇa. All kinds of herbs, metals, even different kinds of flesh of different animals, they are mentioned. Hundreds of different kinds of animals flesh, how it can be utilized for certain disease, the descriptions are there.
Hari–śauri: They use flesh for curing things?
Hari–śauri: They use flesh for curing diseases?
Prabhupāda: Yes. Animal-killing is only allowed when it is absolutely necessary, for medicine. Suppose by killing one animal hundreds of lives are saved, so that is allowed. One preparation is chagalaka-ghṛta. It is prepared… A live goat is put into the ghee with other ingredients, and that is a good medicine for tisis(?).
Prabhupāda: Tisis(?) Tuberculosis.
Overall, to summarize, Srila Prabhupada wasn’t neglectful of his own health or the health of his disciples. In fact, Srila Prabhupada always concluded his letters with: “I hope this meets you in good health.” The underlying principle of Prabhupada’s instructions regarding health was “do the needful” for keeping body and soul together in order to serve Krishna.
Here are two relevant quotes from Srila Prabhupada’s letters to disciples:
“Regarding your physical malady, you should do whatever is required to treat it properly. Whatever is most practical.” (Srila Prabhupada Letter, May 7, 1975)
“One of the symptoms of a devotee is that he is kind, so if our Godbrother becomes ill it is our duty to help him get the proper medicine and treatment so that he can recover.” (Srila Prabhupada Letter, April 5, 1974)
Prahalad Maharaja prays (SB 7.9.19), “My Lord Nṛsiṁhadeva, O Supreme, because of a bodily conception of life, embodied souls neglected and not cared for by You cannot do anything for their betterment. Whatever remedies they accept, although perhaps temporarily beneficial, are certainly impermanent. For example, a father and mother cannot protect their child, a physician and medicine cannot relieve a suffering patient, and a boat on the ocean cannot protect a drowning man.”
In the purport to this verse, Srila Prabhupada states that unless one is protected by the mercy of the Lord, no remedial measure can act effectively. One should consequently depend fully on the causeless mercy of the Lord. “But, as a matter of routine duty, one must of course accept other remedial measures.” Thus, taking necessary treatment for curing ailments in no way undermines our faith in Krishna. As devotees, we do understand that Krishna is the ultimate protector. But it is also said, “do your best and let Krishna do the rest.”