Imagine someone was in a hurry to get high immunity (the Sinopharm jabs are said to be at best only moderately effective) , or there was a free Pfizer booster jab available for a limited time.

What is known about how dangerous (if at all) would it be to get the Pfizer booster just one month after the second Sinopharm jab?

https://www.thenationalnews.com/uae/health/2021/08/11/what-are-the-sinopharm-vaccine-side-effects-and-is-a-pfizer-booster-shot-safe/ says,

"Sinopharm’s Covid-19 vaccine is effective against the Delta variant and can be safely followed with a Pfizer-BioNTech booster shot, researchers have found.

In July, a small study carried out in Sri Lanka found it (sic) to be effective against the highly contagious Delta coronavirus variant.

Moreover, medics in the UAE said the immune system response was very strong once a double dose of the Sinopharm vaccine was topped up with a booster shot of the Pfizer-BioNTech vaccine."

No mention of timing.

Further down the same article it says,

"Dubai residents are eligible to take a booster shot of Pfizer-BioNTech three months after their last Sinopharm dose.

In Abu Dhabi, residents must wait six months after their last Sinopharm dose. They can choose between Pfizer-BioNTech or Sinopharm. Authorities have advised residents to take one Pfizer shot only as a booster. But in some cases they have been able to obtain two doses after receiving a doctor’s consent.

People working in the healthcare sector in Abu Dhabi can receive the booster shot three months after their second Sinopharm dose."

No mention of why it's three or six months for these different groups of people.

Further down it says,

"Anecdotally, people report a (sic) sore arm and minor swelling, with others feeling fatigue or symptoms similar to a cold, which pass in a few days.

In contrast, messenger RNA vaccines, such as Pfizer-BioNTech and Moderna, appear to come with more side effects.

According to a US Centres for Disease Control report, as of December 19, 112,807 people had received the vaccine (sic).

Of these, 3,150 – or 2.8 per cent – had suffered “health impact events”, listed as the inability to perform everyday activities, taking time off work or seeing a doctor as a precaution (sic)."

Even further down the long article it says,

"Concerns have been raised that antibodies to the virus fade quickly.

A large study carried out by Imperial College London in the autumn, involving 365,000 people, showed antibody levels dropped by a quarter in three months."

It's unclear which vaccine they are talking about. Presumably not Sinopharm which is not used much in the UK, which is presumably where the study took place. Antibody levels having dropped by a quarter in three months wouldn't make me use the phrase, "fade quickly". Maybe they meant "dropped to a quarter"?

  • 1
    I don't understand how the quote and link you posted are relevant to safety. Did you mean to say efficacy?
    – Carey Gregory
    Dec 23, 2021 at 6:09
  • @careygregory You're right, think. I've edited the question accordingly. Dec 23, 2021 at 21:56
  • I still don't understand what safety issue you're asking about. The timings of the vaccinations are to address efficacy, not safety. You could probably receive every COVID vaccine currently available all in one day without harm other than a sore arm and some mild flu-like symptoms the next day or two.
    – Carey Gregory
    Dec 24, 2021 at 4:45
  • @careygregory I guess you've answered my question with your comment. A citation would be nice, of course. It's first time I've heard that idea. Why are they saying you have to wait three months or six months before having the booster? Dec 24, 2021 at 6:54
  • 1
    I don't have enough information to make a good answer. They're saying to wait a period of time because they've found that that period of time between doses optimizes the immune response. There are probably people here who can answer this with more detail, but the way your question is composed they're not likely to recognize it. If you simply asked why the waiting periods are recommended, I think you'd get a good answer. I would recommend deleting this question and writing a new one.
    – Carey Gregory
    Dec 25, 2021 at 1:41


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