All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
As long as you can use water you should perform Ghusl from ritual impurity (janabah). If you fear that you will get sick due to going out for Friday prayer after Ghusl, then it is permissible for you to not attend it.
Matalib Uli an-Nuha by ar-Ruhaibani from the Hanbali School of jurisprudence: “A sick person or the one who fears becoming sick is excused for missing the Friday and congregational prayers.”
Abu Dawood narrated on the authority of Ibn ‘Abbas that the Prophet explained the excuse as sickness and fear.
However, your fear of getting sick must not be just an illusion; rather, it must be based on a reason such as an experience in yourself or being informed by a knowledgeable doctor.
Al-Hattab said in Mawahib Al-Jalil: “What appears is that fear is only considered if it is based on a reason, such as having experienced this by himself, or in others that have a similar mood, or with the information of one who knows medicine.
Allah knows best.