Upping time between 2 Pfizer jabs will buy SA valuable time

The government can make the best of a bad situation and buy itself time to fine-tune the vaccine rollout, by stretching the delay between the required two doses of the Pfizer Covid-19 vaccine to three months, experts say.

This follows Health Minister Dr Zweli Mkhize’s announcement earlier this week that due to a recent scientific discovery, recipients of the Pfizer two-dose vaccine regime will wait three months between doses.

According to a recent study in the UK, this amount of time is optimal between doses to allow for the development of antibodies against Covid-19, which will increase the effectiveness of the vaccine.

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South Africa’s rollout to the general public got off to an extremely slow start this week, with fewer than 40,000 vaccine doses being administered by Tuesday afternoon.

Provincial health departments said they were partnering with various community groups and other departments to speed up the registration and vaccination drive for phase two of the rollout.

In the Western Cape, Premier Alan Winde said last week the province gradually increased its vaccination sites from 10 to 18, 8 of which are dedicated to persons over the age of 60.

Delay could be a blessing in disguise

The slow pace of the rollout means South Africa’s tardiness could be used to ensure they sort out their own logistical glitches.

An added benefit of this delay in the South African context is that given the current shortage of vaccines for phase two, government needs to secure more doses and ensure a faster pace in the rollout to avoid a deadly third wave.

Epidemiologist, Jo Barnes, says from an administrative or epidemiological standpoint, delaying the Pfizer dose interval by three months as opposed to the three weeks initially required, will buy the country time.

Government can use this time to sort out logistical and administrative glitches in the Covid-19 vaccine roll-out programme.

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Vaccinologist, Professor Shabir Ahmed Madhi, concurs that spacing out the vaccinations by three months would, in the short term, allow individuals to get at least some protection, considering the constraints in vaccine supply and government’s limited ability to scale up the number vaccination drive.

“With the Pfizer vaccine, it’s also been shown that a wider interval between doses induces a better immune response. Also, in a setting such as SA where a very high percentage of the population has already been exposed to the virus, this will have resulted in them being naturally primed. A single dose of Pfizer vaccine will likely induce a robust immune response that will confer reasonable protection against moderate to severe disease,” Madh said.

Barnes added her concern, however, that the potentially difficult task of tracing all Pfizer dose recipients and ensuring that all of them take the second dose lies ahead. Failure to do this may result in scores of wasted doses.

“It will increase the difficulties for the vaccination teams to trace those persons who received only the first dose and then moved away, changed addresses, lost or changed their cell phones, etc. It remains to be seen whether the advantage of higher immune response can offset the logistical problems and the increased number of half vaccinated persons. No one can at present give a definitive answer on the outcome of that choice.”

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A study supported by the UK Coronavirus Immunology Consortium found that delaying the second Pfizer vaccine dose to 12 weeks significantly increases antibody responses in older people. This makes the vaccine aptly placed in South Africa as it commences its phase 2 of the Covid-19 vaccine rollout focusing on older residents.

Addressing community members during a visit to KwaZulu Natal earlier this week, Mkhize announced his intention to delay the second dose of Pfizer vaccines by up to three months, in light of this finding.

South Africa will be following other countries including Britain, Denmark, Norway, France, the U.S and Canada in extending this interval. SA has so far received just under a million Pfizer vaccine doses, with about 1.3 million more expected by the end of May.

simnikiweh@citizen.co.za