Many poskim and communal leaders have asked me whether parents are obligated to inoculate their children by means of generally accepted vaccines in order to prevent terrible diseases, because some important rabbanim recently expressed the following opinion: Since there is concern that vaccination damages health, not only is it permissible not to vaccinate children, but it is even recommended not to vaccinate them.

In my humble opinion, this is an error. Rather, parents obviously have an obligation to vaccinate their children, and I have ruled that it is even permissible for parents to organize themselves in order to force educational institutions not to accept unvaccinated pupils. I will explain my thinking and my reasoning.


A basic presumption is that there is an obligation to avoid and prevent danger. We find that there are two facets of this mitzvah: passive avoidance and active prevention of danger. In his discussion of the mitzvah of ma’akeh [building a guard rail on a roof] Rambam (Laws of Murder and Preservation of Life 11:4) brings two sources. He writes:

Be it a roof or anything else that presents a hazard that people are liable to stumble upon and die—for example, if one had a well or cistern in his yard, whether or not it contains water—he is obligated to make an enclosure that is ten tefachim [handbreadths] tall, or to make a cover for it, so that a person does not fall in and die. Likewise, there is a positive mitzvah to remove, to safeguard against, and to be exceedingly cautious about any obstruction that endangers life, as it says: “Take utmost care and scrupulously guard your lives” (Devarim 4:9). If he did not remove them, but rather left dangerous obstructions, he has negated a positive mitzvah and transgressed “do not bring blood upon your house” (Devarim 22:8).

Thus, regarding any danger, “there is a positive mitzvah to remove, to safeguard against, and to be exceedingly cautious about” it. We learn from ma’akeh that one must take concrete action to remove danger, and that we are further commanded to prevent danger, as it says, “Take utmost care”. In Minchas Asher on Devarim (Siman 7), I wrote at length on the particulars of this mitzvah and whether it is de-Oraysa or de-Rabanan. Here is not the place to expand upon this.

It would therefore seem perfectly obvious that there is a mitzvah to vaccinate children in order to prevent them from contracting terrible diseases. However, some cast aspersions and claim that since vaccination sometimes causes children to become sick, it is improper to endanger the children in the immediate term in the attempt to prevent future disease and danger.

However, in my humble opinion, this claim is completely and totally devoid of substance, because all studies that were done responsibly establish beyond the shadow of a doubt that, with the exception of mild side-effects, it is not at all common for vaccines to have severe ramifications, and there are no known cases where death was caused by vaccination for certain, even though hundreds of millions of children have been routinely vaccinated. On the other hand, as the number of people who do not vaccinate increases, danger increases as well; if many people refuse vaccination, there is a risk that epidemics will break out and cause mass fatalities, as happened before these vaccines were developed.

The three primary diseases against which the triple vaccination is administered—measles, mumps, and rubella—are terrible diseases. In particular, measles is a horrible disease that entails substantial risk and is more contagious and transmittable from person to person than any other disease known to the medical field.

There have already been measles outbreaks in several centers of Yahadus Charedis. It is known that one baby has died, and others have gotten very sick from this disease. I have written at length in several places (Sheilos u-Teshuvos Minchas Asher, simanim 122-123) about the disagreement between poskim as to whether a person may place himself in limited, remote danger in order to save someone else from major, proximate danger. I concluded that if the risk in question is exceedingly remote and very uncommon, there is an obligation [to save the other person]. Moreover, all would agree that doing so is, at the very least, an act of pious virtue (midas chasidus).

Certainly one is obligated to undergo a procedure that entails some risk in order to treat a disease that is liable to place him in great danger; the disagreement was only about the parameters of the principle that one places his own life ahead of another’s life (“chayecha kodmin le-chayei chavercha”), but it is obvious that all would agree that when it comes to his own life, he is obligated to place himself in remote danger in order to save himself from proximate danger.

Likewise, in the present case, a person is obligated to vaccinate his children because vaccination is not dangerous at all, except in extraordinarily rare cases, whereas lack of vaccination endangers those very children. This is all the more certain given that lack of vaccination constitutes public endangerment.

In truth, this question was already placed on the tables of kings [i.e., was addressed by leading rabbanim] more than 200 years ago, in 5545 [1784-5]. At that time, the English physician Edward Jenner developed the smallpox vaccine. See Tiferes Yisrael (Avos chapter 3, Bo’az 1), who writes that the “righteous Jenner” (“chasid Yenner”) who developed this vaccine is certainly one of the righteous among the nations (“chasidei umos ha-olam”) and will be rewarded in the next world for having saved tens of thousands of lives.

Indeed, this disease claimed many victims before this doctor developed this vaccine, as we find that the Shelah ha-Kadosh wrote (Sha’ar ha-Osiyos, Derech Eretz 13-14), after expanding on the degree to which a person must keep away from danger:

And I am astonished: With regard to the plague of smallpox, called Blattern in German, which spreads among the children—may this never befall us—why aren’t people careful to get the children away and take them out of the city!? These fathers will certainly be held accountable for the deaths of nursing babies who committed no sin and children just weaned from milk who committed no transgression, who died from this sickness, and whose fathers did not spirit them away.

Magen Avraham cites these words (576:3), as does Mishnah Berurah (ad loc. 14).

However, several Acharonim wrote that after the development of this vaccine, it is no longer necessary to take the children away from the city. Rather, they should be vaccinated. So it is written in Zivchei Tzedek (Yoreh De’ah 116:41), who attested that they administer vaccinations on a daily basis, and no one has ever been harmed, and so state Kaf ha-Chayim (ad loc. 60) and Rav Chayim Palache’s Tochechos Chayim (on Parshas Vayeitzei).

This vaccine, developed by the aforementioned doctor, brought about the elimination of the germ that causes this disease, to the extent that it is gone from the world. This is not the case with respect to the measles and the associated diseases mentioned above, which still exist; if people stop vaccinating, there is a real risk of outbreak of these diseases.

In 5745, one of the rabbanim of London, Rav Avraham Hamburg, also known as [Rav Avraham] Nanzig, published a book called Alei Terufah, in which he discusses the question, which was controversial at the time, of whether it is proper to vaccinate, even though in his day there were children who died as a result of the vaccination, or whether it is preferable to do nothing (“shev ve-al ta’aseh adif”).

The Tiferes Yisrael also addresses this question in his commentary on Yoma (8:6). He discusses whether it is permissible to administer this vaccine even though it poses danger, and he concludes that since the danger of not vaccinating is much greater than the danger posed by vaccinating, it is certainly permissible and proper to vaccinate.

In his introduction to Sefer Alei Terufah, the author describes how his little son and daughter were cut down while still flowering—they died of this disease; and how when he lived in the holy community of the Hague in Holland, there was a major outbreak, and many children died; and how when he was in London, once again, many contracted the disease. In the main part of the text he wrote that even if one in a thousand dies from the vaccination, this is not a reason to refrain from vaccinating, just as bloodletting and laxatives are routine. And even though “we have seen several people who faint during bloodletting, and there are reports that in very rare cases someone has died from bloodletting,” one should nevertheless not refrain from these things, which improve wellness and health. The same applies in the present case.

[Rav Hamburg] quotes several contemporary rabbanim who permitted this treatment, even though, in their time, it seems that there were indeed those who became sick and even died from this treatment.

In any event, it is clear and obvious that nowadays it is not only permissible to vaccinate, but there is even an obligation, on order to prevent danger to the individual and the public. Even if in their time, hundreds of years ago, they vacillated, it was only because there were indeed children who died from the vaccine, as is evident from their words. This is not true of today’s vaccines, so there is a bona fide obligation to vaccinate.


I saw that Rav Shlomo Zalman Auerbach, in his Minchas Shlomo (II:82:12), has a major chiddush about taking experimental drugs: Just as we do not worry about risking lives to wage a milchemes mitzvah [a war that it is a mitzvah to wage], so too, marauding beasts like bears and wolves are akin to a milchemes mitzvah, and we do not worry about risking lives to fight against them. The same applies during plagues and epidemics, which have the same status as milchemes mitzvah. Consequently, he permits taking experimental drugs.

But in my opinion, this rationale is very far-fetched. Aside from the fact that it is obvious to me that the laws of waging war apply only to actual wars between nations and armies, not to marauding beasts, and certainly not to sickness and disease, in truth, there is no need or purpose for this rationale, because in the modern world, they neither expect nor allow people to volunteer to take drugs that endanger healthy people. Nor do they administer experimental drugs, except to people who cannot be cured and whose lives cannot be saved by any known means, or unless there is no reason to suspect that these drugs would be harmful to health.

In any event, this is a very innovative rationale that there are good reasons to doubt. Therefore, there is no obligation, no mitzvah, and no permission to endanger oneself in order to advance medical research on experimental drugs. However, this is irrelevant to the case at hand, because the effectiveness of these vaccines has been proven beyond all doubt millions of times, and the danger they entail is miniscule.


It is indeed true that since the vast majority of children and adults in modern society have been vaccinated, these diseases have become exceedingly rare. Therefore, it would seem that there are grounds for parents to claim that they should not endanger their children through vaccination, causing them pain and side-effects, when the expected risk of non-vaccination is so miniscule. However, if we allow these parents not to vaccinate their children, the results would be entirely predictable: many would refrain from vaccinating their children, motivated by maternal compassion and paternal love, and then the great danger of outbreaks of diseases would emerge once again. Therefore, refraining from vaccination is not permitted in any way. In truth, I have ruled, year-in and year-out, that there is an obligation to vaccinate children for this very reason, yet the reality is that more and more parents refrain from vaccinating their children, and we are now witnessing a broad outbreak of the measles.

However, it seems that even if we would say that an individual can evade [vaccination] and still claim that he has kept his child safe, it would nevertheless stand to reason that there is an obligation to vaccinate children, and for two reasons:

  1. I have explained elsewhere that any idea or action that would cause damage and injustice if done en masse, even if it would cause no harm, injustice, or evil when done by an individual, may nevertheless not be done by an individual. It is not just or right for an individual to do what the masses may not do. Such a person is a villain with license from the Torah (“naval birshus ha-Torah”), for due to the honesty of the masses who walk the straight path in their innocence, this person will conduct himself differently and derive unfair benefit.

We learn this from the Bavli, the Yerushalmi, and Midrashei Chazal.

Sanhedrin 109b says that the attribute of the people of Sodom was: “When someone was drying out garlic or onions, each person would come and take one, and would say, ‘I took one.’” And see Rashi ad loc., that each person would say, “I only took something small,” but between all of them, they took everything this person had. Yerushalmi Bava Metzi’a 15a says the same of the people of the generation of the Mabul, explaining that this is the meaning of the pasuk, “the land was filled with thievery.” This likewise appears in Bereishis Rabbah, parsha 31. From their holy words, we learn a fundamental element of just laws: Anything that would be wicked or unjust if done en masse is forbidden for an individual to do.

The same law and the same reasoning apply in the present case. It is only because most people vaccinate their children, thereby causing them pain, that the minority can refrain from vaccination. However, the more people refrain from vaccinating their children, the greater the danger, to the extent that if most people would act in this manner, things would revert to what they were; we would return to the medieval era, and hundreds of thousands would die from terrible diseases. In cases like this, the obligation to vaccinate applies to each and every individual.

I know that there is room to engage in mental acrobatics and distinguish between an act of commission (“kum ve-asei”), which would be forbidden, like those who stole less than the value of a perutah, and an act of omission (“shev ve-al ta’aseh”), like refraining from vaccination; moreover, one can claim that maybe this only smacks of a prohibition when many people come at once and steal everything that their fellow has, like the generation of the Mabul and the people of Sodom did. However, in my humble opinion, it makes more sense that there are no grounds to make such a distinction, for in their essence the cases are similar, as is clear to anyone with understanding and intelligence. Indeed, the facts have been proven. Reality—that many people have been refusing vaccination recently, and now many children have caught the measles—is slapping us in the face.

  1. It seems that this halakhah can be derived from the obligation of all residents of a city to take part in guarding the city and repairing its walls, as explained in Bava Basra (8a) and in Shulchan Aruch (Choshen Mishpat 163). Just as all residents of the city must either share in the actual guarding or the expenses of guarding the city, and even though it is clear that if one person shirks his duty to guard or pay the walls will not crumble and the enemy will not prevail, the obligation to guard the city nevertheless applies to each person equally, and no individual may dodge it, so too in the present case. For everyone is a partner when it comes to anything that is for the betterment of society or a public necessity. Each person must contribute his equal share, and there is no difference between a financial obligation and the obligation to vaccinate. The same law applies to both.

This all applies in a case where one can refrain from vaccinating his children without risking their health, because enough others do vaccinate. The present situation is far more severe, though, and we need not resort to creative readings of aggados to determine that vaccination of children is obligatory. The disease has broken out already, and every parent who refuses to vaccinate his children is placing them directly in harm’s way.

Translated by Elli Fischer

This translation has been reviewed and approved by Rav Asher Weiss.