https://www.ncbcenter.org/index.php/download_file/view/33/182/
(This is linked by the NCBC, but is to a Vatican document.)
This Pontifical Academy for Life, carrying out the commission entrusted to us by the Congregation for the Doctrine of Faith, in answer to your request, has proceeded to a careful examination of the question of these “tainted” vaccines…
…
As regards the diseases against which there are no alternative vaccines which are available and ethically acceptable, it is right to abstain from using these vaccines if it can be done without causing children, and indirectly the population as a whole, to undergo significant risks to their health. However, if the latter are exposed to considerable dangers to their health, vaccines with moral problems pertaining to them may also be used on a temporary basis. The moral reason is that the duty to avoid passive material cooperation is not obligatory if there is grave inconvenience. Moreover, we find, in such a case, a proportional reason, in order to accept the use of these vaccines in the presence of the danger of favouring the spread of the pathological agent, due to the lack of vaccination of children.
…
the lawfulness of the use of these vaccines should not be misinterpreted as a declaration of the lawfulness of their production, marketing and use, but is to be understood as being a passive material cooperation and, in its mildest and remotest sense, also active, morally justified as an extrema ratio due to the necessity to provide for the good of one’s children and of the people who come in contact with the children (pregnant women);