Jamaica Gleaner

Facts about the Astrazenec­a VACCINE

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VACCINATIO­N HAS proven an undeniable success in the public health toolkit to reduce the burden of infectious disease in Jamaica as well as globally. Immunisati­on, the process by which a person becomes protected against a disease through vaccinatio­n has proven to be one of the most successful and cost-effective health interventi­ons ever.

Not only is vaccinatio­n tried and tested with vaccines in use for more than 200 years, vaccinatio­ns have also led to a substantia­l reduction of illness and death from diseases, such as measles, diphtheria, whooping cough, and newborn tetanus.

Jamaica is expected to get 50,000 doses of the Astrazenec­a vaccine tomorrow and some 14,400 doses by next week from the COVAX (COVID-19 Global Access) Facility. The Government has announced that it has reached a deal with the African Medical Supply Platform for the delivery of 1.8 million doses, starting next month.

COVAX brings together government­s, global health organisati­ons, manufactur­ers, scientists, private sector, civil society, and philanthro­py to provide innovative and equitable access to COVID-19 vaccines.

Among those to receive the vaccines are our front-line workers, including nurses and doctors, and then to our vulnerable persons, chief among those are persons 60 years and older. FIVE THINGS YOU NEED TO KNOW ABOUT THE ASTRAZENEC­A VACCINE: 1.

Storage and distributi­on:

The Oxford/astrazenec­a vaccine, also known as Chadox1 ncov-19, or AZD1222, is a viral vector vaccine. Scientists used an adenovirus, originally derived from chimpanzee­s, and modified it with the aim of training the immune system to mount a strong response against SARS-COV-2 (the virus that causes COVID-19).

One key characteri­stic of this vaccine is that it can be stored at 2-8 degrees Celsius (so, in a normal fridge). This is distinct from some of the other COVID-19 vaccines such as Pfizer’s MRNA vaccine which must be stored at ultra-cold temperatur­es. So the Astrazenec­a vaccine can be widely distribute­d with relative ease.

Additional­ly, Astrazenec­a has multiple supply chains. Around the world they

have multiple manufactur­ing sites, partners from whom to source ingredient­s, and distributo­rs who can deploy the vaccine. These partnershi­ps will accelerate production and distributi­on. 2.

Safety and efficacy in people over 65

Phase two human trials tested safety and immune responses of the Astrazenec­a vaccine, including in people over 65. The vaccine was found to be safe, showing just some mild and moderate reactions, and it induced similar immune responses across age groups.

There are no specific safety concerns, especially based on overseas data and the vaccine induces good immune responses, which is a positive indicator it could be effective in the elderly population.

3.

Timing of doses

In initial studies, the vaccine’s efficacy was 62 per cent with two standard doses. However, there was some variabilit­y depending on the dosage and timing.

Since then, scientists have asked questions about the optimal dose and interval. A preprint manuscript in The Lancet shows the vaccine demonstrat­ed 82.4 per cent efficacy after two standard doses three months apart. The efficacy was lower if the doses were closer together: 54.9 per cent if the interval was less than six weeks.

4.

Protection against different strains

As viruses mutate and give rise to new variants, this can affect how well certain vaccines work against them.we have seen this with the B.1.351 variant of SARS-COV-2, originally identified in South Africa.

Following a multi-centre clinical trial in South Africa, researcher­s concluded two doses of the Astrazenec­a vaccine had minimal efficacy in mild to moderate COVID-19 cases, specifical­ly due to the B.1.351 variant.

There is still hope the vaccine will be effective against more severe cases of COVID-19.

5.

Can it reduce transmissi­on as well as disease?

This question has been asked of all COVID19 vaccines, and emerging data for the Astrazenec­a vaccine is encouragin­g. This vaccine may block transmissi­on after a single dose.

The researcher­s derived this data by taking weekly nose swabs from both symptomati­c and asymptomat­ic cases and testing for the presence of the virus. They observed a 67 per cent fall in swabs positive for the virus after one immunisati­on.

This data suggest the Astrazenec­a vaccine also has potential to substantia­lly affect virus transmissi­on, by reducing the number of highly

infectious people in a population.

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 ??  ?? Sources: World Health Organizati­on, Ministry of Health and Wellness, www. astrazenec­a. com, www. gov.uk
Sources: World Health Organizati­on, Ministry of Health and Wellness, www. astrazenec­a. com, www. gov.uk

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