Yes, individuals may still be at risk of contracting COVID-19, although the disease will likely be milder in comparison to those who are unvaccinated. More evidence is required to confirm whether COVID-19 vaccines provide protection against asymptomatic or mild disease. Presently it remains unclear whether vaccinated individuals can still spread the disease to others, therefore caution is still required.

The most common side effects include tenderness at the injection site, headache, fever, fatigue, chills or diarrhoea. These side effects range from mild to moderate, and may feel similar to a flu-like illness for a couple of days.

The body’s immune system takes up to 14 days to develop strong immune responses after the first dose of the Johnson and Johnson vaccine. With mRNA vaccines (e.g. Pfizer), there is some protection two weeks after the first dose, but the best protection is achieved after the second dose. There is good data emerging to show that breakthrough asymptomatic infections (COVID-19 infections following vaccination) are uncommon within 10 days (1 in 100) after one dose, and extremely uncommon (1 in 1000) after two doses of an mRNA vaccine (Pfizer or Moderna vaccines). The infections following vaccination are usually mild and do not require hospitalisation.

Yes, according to Government regulation masks are to be worn indoors. Presently it unclear if COVID-19 vaccines provide complete protection from infection with mild COVID-19, however the evidence shows that COVID-19 vaccines protect from severe disease, hospitalisation and death. 

At the moment there is not enough evidence to confidently answer this question. Scientists are monitoring those who have received vaccines in order to answer this question.

All these are mild side effects and indicate the expected immune response to the vaccine. You do not need to take any medication, but if you wish you can take paracetamol.

No, it is not necessary. Whilst vaccination will cause almost all people to develop antibodies to the spike protein after receiving a COVID-19 vaccine, a few people will not develop measurable antibodies. However, even people who do not develop antibodies to the spike protein are still likely to be protected on account of protective cellular responses (T-cell responses). A few health care workers who have enrolled in the Sisonke Johnson & Johnson trial have reported absence of antibody and cell mediated responses. Sisonke released a statement explaining the reasons for this. 

There may be different reasons why antibody tests for SARS-CoV-2 are negative after a person has been vaccinated.

  • Antibody tests detect antibodies to different parts of the SARS-CoV-2 virus. Some antibody tests detect antibodies to the ‘N-protein’ (nucleoprotein), and some detect antibody responses to the ‘spike protein’, whilst some detect both kinds of antibodies. As the vaccine will only cause a person to develop antibodies to the ‘S-protein’, a person who has received the vaccine will not develop antibodies to the ‘N-protein’. Therefore an antibody test based on the ‘N-protein’ will be negative.
  • Antibodies following vaccination take a few weeks to develop. A negative antibody test may indicate that the test has been done too soon after vaccination.
  • A person who has received the vaccine and does not have antibodies to the ‘S-protein’ even after several weeks may be one of the very few persons who does not develop antibodies at all. Currently experts still believe that these persons have some immune protection against SARS-CoV-2, because of cellular immune responses.

Not all samples are tested for the variant. There is cross protection, which means if you were infected with one variant, it will give protection against others.