I have been trying to write a summary of all of the recent Church statements and documents about COVID-19 and the moral issues involved. In the meantime Michael Deem has written one titled "The ultimate Catholic coronavirus vaccine morality explainer." I encourage you to read the article and if you have time to read the sources that he cites.
Below is a summary of the main points, taken from the article.
"Acceptance of the COVID-19 vaccines developed, researched, or tested utilizing fetal cell lines is morally permissible when no alternative COVID-19 vaccine is available or accessible.
Acceptance of these COVID-19 vaccine involves very remote material cooperation in the twofold evils of the abortions of the fetuses from whom tissue was posthumously taken to derive cell strains for medical research.
An action that involves remote cooperation in evil is permissible, or even encouraged, when there are grave moral reasons that are proportional to or outweigh moral badness of this cooperation.
The proportional moral reasons for acceptance of the vaccine are the promotion of community health and prevention of serious risk of harm, which are grounded in the fundamental moral and social principle of the common good.
It is permissible to refuse the COVID-19 vaccine, but those who refuse should perform additional actions that promote community health and prevention of serious harm.
While accepting the vaccine is a morally responsible action, recipients nonetheless have an obligation to protest the use of fetal cell lines in vaccine development."