Comparing COVID Vaccine to Other Vaccines

Comparing COVID Vaccine to Other Vaccines April 21, 2021

For decades, Catholic ethicists have approved of several vaccines in the USA which have some connection to abortion. It is worth comparing these to COVID vaccines. I think that given they can ethically be used, a fortiori the main COVID vaccines can be used. I will compare them on various grounds. I focus on rubella and chickenpox here although Hepatitis A has similar issues to the two of them.

Here is a summary of the results. (Sources in text.)

Connection to   fetal cell lines   
Two vaccines   currently used in the USA only tested on fetal cell lines. Some others are grown   on fetal cell lines.   
Grown on a   fetal cell line   
Grown on a   fetal cell line   
Which fetal   cell lines   
Most use   HEK-293 which is immortalized and used for tens of thousands of experiments   & may be a miscarriage, not abortion.   
MRC-5 and   WI-38 which are not immortalized and used much less   
Mortality   pre-vaccine   
Between 1 in   50 and 1 in 200   
About 1 in   5,900: almost all rubella deaths are of the unborn or neonatal babies.   
About 1 in 60,000
Human trials   
One single COVID   trial: 21,830   
Between   14,000 & 20,000 over different trials and different vaccines for rubella   
Total tested:   11,102   


Fetal Cell Connection

Various vaccines in front of an American Flag
Various vaccines in front of an American Flag (CC BY 2.0 Marco Verch)

Many different things like most drugs, some “artificial flavors” in food, and many cosmetic products are tested or developed on fetal cell lines. We should support the elimination of these lines and their replacement with fully ethical lines.

Nonetheless, when looking at how these lines are used, it is pretty clear that a single test done once and not repeated is much less connected than growing each new batch on a cell line. In fact, all declarations I’d seen prior to 2020 on concerns about fetal cell lines and vaccines were concerned only with those grown on fetal cell lines, not those merely tested as this is a whole other degree of remoteness.

As the test does not directly affect the vaccine you receive, it is not even cooperation but only appropriation. Cooperation would indicate your act in some way, shape, or form contributes even in the tiniest way to some current or future evil act. Even if millions rejected these vaccines, fetal cell lines would not be used less as the experiment was already done. Also, a test does not continually require more cells from that line like growing the vaccine would.

This is why I and others have indicated that if given the option, choose a COVID vaccine only tested on a fetal cell line. Both currently used COVID vaccines in the USA are only tested on a fetal cell line.

For comparison, all the Rubella and Chickenpox vaccines in the USA are grown on fetal cell lines.

Which Fetal Cell Line

Fetal cell lines are cells that descend from fetuses. Some are simply in suspended animation to keep them within the Hayflick limit for human cell division while others are “immortalized” to go beyond that but not necessarily indefinitely. (The Hayflick limit is that after a certain number of divisions human cells tend to start to reach senescence or old age. It’s really interesting and shows we age at the molecular and cellular level. As far as cell lines, it matters as there is clearly a limited number of cells that can be produced before the Hayflick limit is reached.) An immortalized cell line is preferred as it will last much longer and each cell is a much smaller portion of the total possible cells in that line. Thus, it is less likely to encourage creating future cell lines from abortion. Also, using more commonly used cell lines are also preferred as that is also less likely to create demand for new fetal cell lines.

In fact, we know that Walvax-2 was created in 2015 and specifically intended to replace the non-immortalized MRC-5 fetal cell line. However, no line has yet been created to replace an immortalized cell line.

Rubella and Chickenpox vaccines are grown on WI-38 and/or MRC-5, neither of which are immortalized. Also, these two are far less commonly used than HEK-293.

For comparison, the two COVID vaccines available in the USA right now use HEK-293, an “immortalized” cell line, in testing. The chart shows HEK-293 is the most commonly used one for COVID vaccines and part of that has to do with that it was the first cell line scientists where isolated COVID-19 interactions on a cellular level so then existing results could be used as the comparison rather than having to run your own comparison.

Death Rate

The death rate for COVID is somewhere between about 1 in 50 and 1 in 200. Sources vary, mainly based on how many unconfirmed cases of COVID they estimate exist. These scientists estimated a high number of unconfirmed cases and got about 1 in 167 or 0.6%. This estimate based solely on confirmed cases gets 1 in 56 or 1.8%. as you have likely seen, the death rate for COVID increases dramatically with age.

Rubella killed almost no people who had been born when they catch it: the death rate is so low as to be hard to find. However, it often caused miscarriage, neonatal death, and birth defects if a pregnant mother gets it. A pre-vaccine epidemic of rubella in the USA in the early 1960s affected 1 in 100 pregnancies, causing thousands of deaf, blind, or mentally retarded children. It caused a neonatal death at a rate of about 1 per 5,900 infections.

Chickenpox killed about 1 in 60,000 before vaccines. It was 1 in 100,000 before age 15 but 21 in 100,000 past age 30.

All three of these diseases have a death rate that varies substantially by age. This shows that we vaccinate not just for ourselves but for others. Rubella shows this most clearly as we all got vaccinated to save unborn babies. Personally, I am more concerned about accidentally infecting an elderly person with COVID than with dying from COVID myself.

Human Trials

Some argue that the COVID vaccine should be avoided as it is experimental or has insufficient testing. Let’s compare its testing to these other two vaccines grown on fetal cell lines that the Church has said can be ethically used.

Pfizer alone in a single trial (their main phase III trial), gave at least 21,830 people their COVID vaccine to test it. The test was twice that size as half were given a placebo to compare efficacy. Other COVID vaccines are getting similar numbers in large stage III trials.

Rubella is a little complicated as it had separate trials and then trials with Measles and Mumps in the MMR vaccine, and because different vaccines for rubella have been developed over the years either for independent use or for use in an MMR combination vaccine. This report indicates that overall, between all the trials, just over 28,000 have been tested. It seems that many of these would have been given a placebo, but there is no indication how many. As most bigger trials have a placebo control that means somewhere between 14,000 and 20,000 have gotten a rubella vaccine over a whole slew of trials of different rubella vaccines.

Merck, the manufacturer of the standard chickenpox vaccine notes in their application which the FDA approved, “Overall, 9454 healthy children (12 months to 12 years of age) and 1648 adolescents and adults (13 years of age and older) have been vaccinated with Oka/Merck live attenuated varicella vaccine in clinical trials.” That is a total of 11,102 trial participants.

This indicates that COVID vaccines have significantly more human trial participants than either of the other two vaccines. Phase III trials lasted about as long.


The tradition of the Church has clearly indicated that remote cooperation can be ethical. The more remote that cooperation is, the less of a bearing it has on ethics. (For example, I think we can all see how a janitor at a Planned Parenthood office, although technically remote, has a lot more of a moral obligation to avoid it than we have a moral obligation to not pay taxes as some funds Planned Parenthood. In fact, given all the other circumstances, I would recommend paying taxes while trying to change where tax money goes through the pollical process.)

The Church and top ethicists have also ruled repeatedly that the remote cooperation in abortion with rubella and chickenpox vaccines is morally acceptable. (The Vatican [a 2nd time (#35d), & a 3rd time], the English Bishops, the National Catholic Bioethics CenterCatholic Medical Associationan Archbishop with a bioethics doctoratea priest with doctoral degrees in both moral theology and microbiology, most Catholic moral theologians and bioethicists, and even the SSPX all agree that it is permissible to get such vaccines.) This was with the lesser number of trial participants. Even with this health risk much lower than COVID, the Church ruled there was sufficiently grave danger to health to use these vaccines.

Given that the COVID is much more deadly and noticeably less connected to abortion, all those rulings about the prior two vaccines apply a fortiori to COVID vaccines. (A fortiori is a method of arguing where you show something less evident, then move to something more evident and indicate the same principles apply, but even stronger than in the prior case.)

There are dozens of other things we should abject to first involving abortion and other objective intrinsic evils before rejecting a COVID vaccine. Most of them are far less necessary (some drugs aren’t) and often far more connected to intrinsic evil. To demonstrate how different these degrees of remoteness were, I estimated spending $6.61 on Chinese-made goods contributed as much to a future abortion (via Chinese forced abortion programs) as 1 billion people using one of the two vaccines in use in the USA.

Let’s oppose abortion but let’s not create false rigorist interpretations of Catholic moral theology. People should follow their conscience but priests like me have a duty to inform your conscience. It is licit to take the COVID vaccine as the cooperation is extremely remote. Given the other surrounding circumstances like the risk to self and others, all Catholics should take the COVID vaccine if medically recommended to do so.

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