J&J vaccine: the viral vector approach

The J&J vaccine is based on decades of research. It uses a harmless version of an adenovirus (which cause colds), which is called a vector. 

An adenovirus can’t make you sick or cause disease, can’t replicate and can’t integrate into your DNA. 

The vector is like an envelope that delivers spike protein-making genes to your cells. 

Your cells pull in the adenovirus, and start making spike proteins.

These spike proteins go to the outside of cells, where your immune system can see and respond to them. 

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J&J fast facts

  • The J&J COVID-19 vaccine is a single shot into the upper arm.
  • Protection starts around 10 - 14 days after vaccination. 
  • The vaccine does not contain any animal products and is halaal.
  • You cannot get COVID-19 from the J&J vaccine.
  • The J&J vaccine can be safely stored in a normal refrigirator for one month, making it much easier to use and distribute.
  • Aspen Pharma will produce the J&J vaccine. South Africa is likely to get 30 million doses.
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Vaccine safety

The J&J vaccine has received validation from the World Health Organization. It has so far been safely given to millions of people around the world. 

In February 2021, the J&J vaccine was approved by South African Health Products Regulatory Authority (SAPHRA) under the Sisonke protocol, for an implementation study among 350,000 to 500,000 healthcare workers.

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Testing & approving the vaccine in SA

On 31 March 2021, SAPHRA registered the J&J coronavirus vaccine under conditions which include safety monitoring. 

It was studied in a trial of 4,984 people in South Africa. During the trial, 94.5% of all COVID-19 cases among study participants were caused by the 501Y.V2 variant.

Overall, the vaccine was 64% effective at preventing moderate-to-severe COVID-19 and 81.7% effective against severe to critical COVID-19 at 28 days post-vaccination.

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Possible side effects

Vaccines have side effects, which are caused when the immune system reacts to them. 

This sometimes confuses people, who think that the vaccine has made them sick. But it really means that the vaccine is working. These side effects, which are usually mild, last for a day or two. 

Side effects can include:

  • Fever.
  • Pain or swelling near the injection site.
  • Chills.
  • Aching muscles and joints. 
  • Feeling tired.
  • Nausea and/or vomiting.

Some people have a severe allergic reaction to vaccines, but this is very rare and can be treated. 

It is important to let health care workers know if you have ever had a severe allergic reaction in the past – or if you have allergy symptoms after getting vaccinated.

If you develop any of the following symptoms after getting the J&J vaccine, seek medical attention right away:

  • Shortness of breath
  • Chest pain
  • Persistent abdominal pain
  • Swollen legs
  • Severe or persistent headache
  • Blurred vision
  • Persistent bleeding
  • Skin bruising
  • Small round spots that appear a few days after getting the vaccine.
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A slight risk of blood clots

In April 2021, use of the J & J vaccine was briefly paused in South Africa. 

This happened because of very rare cases of abnormal blood clots, which can be life-threatening. In the US, these rare blood clots developed in 15 women – of eight million people who got the J&J  vaccine. 

So far, these rare blood clots have developed mostly in women under 50 years old. 

The  vaccine is now recommended and being used again with screening for people at high risk for blood clots, monitoring people after they get the vaccine, and treating people who develop these rare blood clots.

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Very low* risk of Guillain-Barré syndrome

In July 2021, the US FDA added a warning to J&J’s COVID vaccine about an increased risk of Guillain-Barré syndrome (GBS). 

GBS is a rare condition that happens when the immune system attacks nerve cells.  Other vaccines have been linked with GBS – as has COVID-19 – but the overall risk is very low, and it is outweighed by the benefits of vaccination. 

The cases were mainly in men aged 50+, and usually occurred two weeks after vaccination. 

Early symptoms of GBS include weakness, tingling or numbness in the arms and legs, double vision, and difficulty walking, speaking, chewing, swallowing or controlling your bladder or bowels – which can progress to widespread muscle weakness and paralysis. 

See a doctor if you develop any of these symptoms after receiving the J&J vaccine.

*Among 12.9 million people in the US who got the J&J vaccine, here have only been 100 cases of GBS. 

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The J&J vaccine is...

  • Given as a single dose.
  • Safe and effective at preventing COVID-19 28 days after vaccination.
  • Safe for people living with HIV, and can be used with antiretrovirals. 
  • Safe for people with pre-existing conditions that put them at higher risk for falling seriously ill from and dying  of COVID-19.
  • Possible for pregnant and breastfeeding women to use.
  • Just as effective for Black people (based on information from clinical trials) as people of other races/ethnicities.
  • 64% effective against the 501Y. V2 coronavirus variant (mild/moderate disease), in a clinical trial in South Africa. 
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The J&J vaccine is NOT...

  • Given as two shots (although it might be in the future)
  • Effective forever – as with all covid vaccines, we don’t know how long protection lasts. The virus may keep changing, so boosters will be needed. 
  • Going to stop the pandemic right away – people will still need to wear masks and socially distance until enough people have been vaccinated.  
  • Approved for use in people under age 18 because it is still under study.
  • Able to have an impact on fertility or pregnancy. 
  • Able to track or control people’s movements.
  • Not always effective against coronavirus variants.
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How to get vaccinated

New information on vaccines is coming out all the time. The health department has set up this page:

You can register on the Electronic Vaccination Data System (EVDS):

1. Online at

2. Using the WhatsApp line 0600 123456.

3. Via SMS by dialling *134*832#.

4. Call the COVID-19 hotline 0800 029 999.

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When to get vaccinated

South Africa’s vaccination plan started in April 2021. The target is to have everyone aged 18 years and older vaccinated by February 2022.

The health department says this will be up to 40.4 million people.

The roll-out is by age groups (oldest first), some jobs (health workers) and some settings (such as old-age homes). Watch out for your turn and also help and encourage your friends and family when it’s their turn to be vaccinated.