Does the Catholic Church have an official position on medical passes (“vaccine passes”) being required to attend Mass?
The short answer is no. I rather doubt that the sacraments or attending Mass will ever be for the double vaccinated only.
As for the moment, the Church encourages the faithful to get vaccinated, but it will never publicly mandate it as a moral obligation. The individual conscience of each of the faithful is to be respected on this issue.
Whether a government will try to mandate such a decree is another matter. That will definitely open up a new can of worms!
Rome has already made it clear that the faithful are not morally obliged to receive a vaccine.
At the same time, practical reason makes evident that vaccination is not, as a rule, a moral obligation and that, therefore, it must be voluntary. In any case, from the ethical point of view, the morality of vaccination depends not only on the duty to protect one's own health, but also on the duty to pursue the common good. - Note on the morality of using some anti-Covid-19 vaccines
Thus if the vaccines are looked upon as something voluntary; it makes no sense that the Church would required it for Mass attendance. However, I do fear that governments may try to make it an obligation, in which case the Church will have to defend the rights of the laity in this matter.
The battle line is being set up, so be prepared.
The following articles may be of interest:
Even if certain dioceses have made guidelines for their respective dioceses, these guidelines simply involve that particular diocese and are not considered an official position for the Universal Church.
For example the Diocese of Moncton, New Brunswick requires the faithful to be double vaccinated in order to attend Mass. I would expect this to eventually be challenged in court and at Rome!
Rome could eventually leave this decision to the local ordinaries (Bishops), but at the present moment has not done so.
On September 24, 2021, the Canadian Archdiocese of Moncton has rescinded a policy that required all Catholics wishing to enter church buildings to show proof of having received two doses of a coronavirus vaccination and record their names with volunteers.
The new policies appear in line with the Church’s own internal assessment of vaccines and public health protections during the pandemic.
Pope Francis and the Congregation for the Doctrine of the Faith in Rome have made clear that it is morally acceptable for Catholics to receive all of the widely available vaccines against coronavirus, and stated repeatedly that doing so is a service to the common good. The CDF has also insisted that vaccination is a matter of prudential moral freedom for the individual.
The new Moncton policy, now common to all the dioceses of the province, provides that “it is highly desirable for parish employees to be fully vaccinated.” “If this is not the case, they will have to wear a mask at all times and undergo a COVID test periodically according to government policy.”
“We will accept anyone who comes to the parish offices to get information or service. If this person is not vaccinated, they must wear a mask,” the archdiocese said. - Canadian archdiocese drops vaccine registry for Mass