It's okay to be concerned about the COVID-19 vaccines. But concern means you learn about them, and do some credible research or ask experts who'd be able to answer the questions you have. Concern does not mean you start spreading hysteria.

All the COVID vaccines currently authorised for use, including the Oxford AstraZeneca, Pfizer and Moderna vaccines are authorised only for emergency use, but all have gone through research and clinical trials and have been proven to be effective against COVID-19.

All the COVID vaccines, do have precautions depending on allergies and pre-existing conditions you should let your doctor know about, and a likelihood of some side effects; much like almost any other vaccine or medicine you have ever taken in your entire life.

The COVISHIELD being sent to Maldives from India, by SII was co-developed is the Oxford AstraZeneca vaccine, (a rose by another name, smelling just as sweet). SII just has a production and distribution alliance on the Oxford AstraZeneca vaccine and has called it COVISHIELD.

In regards to efficacy, as per articles, the Pfizer and Moderna vaccines seem to have a higher efficacy but it could also be because in their trials, they were checking for symptoms of COVID-19, while in the Oxford AstraZeneca one they were testing for COVID-19, not just symptoms

There are some articles that share concerns that a vaccine with a lower efficacy may not be able to provide us with the herd immunity required, but even they agree that it would be even worse, if people didn't take the lower efficacy vaccine.

The Oxford AstraZeneca vaccine is a viable, safe and more feasible vaccine available and authorised for use. Both Pfizer and Moderna vaccines would require immense logistical and financial burdens just to transport and administer them.

It might be kinda like going to USA to buy asprin when your kanmathee fihaara has panadol.

Also, noting that I am not an expert and much of the information I have shared in this thread are from the links below:

You can access the fact sheets for COVISHIELD, Pfizer and Moderna vaccines through the links below:
COVISHIELD: https://www.seruminstitute.com/pdf/covishield_fact_sheet.pdf
Oxford AstraZeneca: https://www.gov.uk/government/publications/regulatory-approval-of-covid-19-vaccine-astrazeneca/information-for-uk-recipients-on-covid-19-vaccine-astrazeneca
Pfizer: https://www.fda.gov/media/144414/download
Moderna: https://www.fda.gov/media/144638/download