Intramuscular injection is the recommended route for all COVID-19 vaccines.

The recommended site to administer an intramuscular injection to an adult is the deltoid muscle.

The recommended dosage is two doses given intramuscularly (0.5ml each) with an interval of 8 to 12 weeks. 

Common side effects to vaccination may include injection site pain and swelling, fever, chills, tiredness, and headache. For most people, side effects last no longer than 1-2 days. A side effect is not a contraindication to a second dose.

Persons with an immediate allergic reaction to the first dose of a COVID-19 vaccine should not receive additional doses of the same COVID-19 vaccines. An immediate allergic reaction to a vaccine or medication is defined as any hypersensitivity-related signs or symptoms consistent with urticaria, angioedema, respiratory distress (e.g., wheezing, stridor), or anaphylaxis that occur within four hours following administration.

Providers should attempt to determine whether reactions reported following vaccination are consistent with immediate allergic reactions versus other types of reactions commonly observed following vaccination, such as a vasovagal reaction or post-vaccination side effects (which are not contraindications to receiving the second vaccine dose).

No. Given the lack of data on the safety and efficacy of COVID-19 vaccines administered simultaneously with other vaccines, the vaccine series should be administered alone with a minimum interval of 14 days before or after administration with any other vaccines. 

There should be a minimum interval of 14 days before or after administration with any other vaccines. However, if a COVID-19 vaccine is inadvertently administered within 14 days of another vaccine, doses do not need to be repeated for either vaccine. Additionally, if the only opportunity for vaccination occurs during this 14-day interval and you do not expect the patient to return, you may vaccinate them.

At this time, we do not know if COVID-19 vaccination will have any effect on preventing transmission. Some people can be infected with the virus that causes COVID-19 but remain asymptomatic.  It is important to know whether COVID-19 vaccines can help reduce the number of people that have asymptomatic infection as these people can unknowingly spread the virus to others.

The potential for asymptomatic transmission of the virus that causes COVID-19 underscores the importance of applying infection prevention practices, including physical distancing, respiratory and hand hygiene, surface decontamination, and source control, to encounters with all patients while in a healthcare facility. Vaccination providers should refer to the guidance developed to prevent the spread of COVID-19 in healthcare settings, including outpatient and ambulatory care settings.

No substantive data are available related to impact of Covid vaccine on transmission or viral shedding.

In the meantime, we must maintain and strengthen public health measures that work: masking, physical distancing, hand washing, respiratory and cough hygiene, avoiding crowds, and ensuring good ventilation.

https://www.cdc.gov/vaccines/covid-19/hcp/faq.html

https://www.who.int/news-room/feature-stories/detail/the-oxford-astrazeneca-covid-19-vaccine-what-you-need-to-know