Connect with us


Efficacy of Covid-19 vaccines will drop during mass inoculations: Thai virologist




PHOTO: Siam Rath

Thai virologist Dr. Yong Poovorawan from Chulalongkorn University, has spoken about claims that the efficacy of every vaccine available today, including Covid-19 vaccines, tend to lower after being used in mass inoculations, compared to the findings from the laboratory during human testing trials.

He recommends that people should not rely solely on the vaccines alone because uncertainty will remain during the roll out phase of the new inoculations.

“The best way to protect themselves is to practice basic safety standards as we usually do today… wearing face masks all the time when going outside and in crowded venues, regularly washing hands, and maintain social distancing.”

On his Facebook page, Dr. Young cited the case of Hepatitis B vaccines that claimed between 94-95% efficacy. But after use on mass populations, its efficacy dropped to about 80%. He believes this trend will be the same as Covid-19 vaccines.

“Although the manufacturers claim the vaccines’ high efficacy, that is just the laboratory results. In practice, several variables may cause lower effectiveness of the vaccines.”

He also says that the real effectiveness of Covid-19 vaccines, both the American from Pfizer and the Chinese from Sinopharm will be known soon after the populations of Israel and UAE have been inoculated in large numbers already.

SOURCE: Thai PBS World


Get more from The Thaiger

📱 Download our app on Android or iOS
👋 Have your say on our Thailand forums
🔔 Subscribe to our daily email newsletter
📺 Subscribe / Join YouTube for daily shows
👍 Like/Follow us on Facebook
🐦 FOLLOW us on Twitter
📷 FOLLOW us on Instagram


Join the conversation and have your say on Thailand news published on The Thaiger.

Thaiger Talk is our new Thaiger Community where you can join the discussion on everything happening in Thailand right now.

Please note that articles are not posted to the forum instantly and can take up to 20 min before being visible. Click for more information and the Thaiger Talk Guidelines.



  1. Avatar


    Saturday, January 23, 2021 at 8:08 am

    looks like the quarantine and the other hoops to jump through will be with us for a long time yet then. What’s needed is a super accurate test that can detect the very small viral loads that are present 2 – 3 days after infection, if that can be developed, at least quarantine period could be significantly reduced.

    • Avatar


      Saturday, January 23, 2021 at 11:17 am

      What’s needed is for our childish media and medical PR shills to grow up and accept that we take small risks every day.

      I invite you to spend the rest of your life in lockdown. That is a right which you most certainly have.

  2. Avatar

    brian mc

    Saturday, January 23, 2021 at 8:46 am

    well, it will just prove the verve were right if the drugs don’t work. it was foretold in the 90’s

    • Avatar

      Sam Charles

      Saturday, January 23, 2021 at 9:43 am

      was that the 1590’s ….. tin foil hat society posting their BS again

  3. Avatar


    Saturday, January 23, 2021 at 11:15 am

    So lockdowns and mask forever? No thanks.

    Once again, we confront the reality that herd immunity is the future. I’ll take my chances with the 0.2% fatality rate. Polio and the measles are worse than COVID, yet your grandparents lived with these.

    Covid panic warriors need to GROW UP!

    • Avatar

      Issan John

      Saturday, January 23, 2021 at 12:16 pm

      Then go and take your chances elsewhere, where your selfishness and stupidity don’t affect others.

      • Avatar


        Saturday, January 23, 2021 at 2:39 pm

        I will take my selfLESSness and intelligence elsewhere, thanks.

        YOU exhibit selfishness and stupidity daily. Unlike you, I don’t believe others should be forced to sacrifice for my own wellbeing.

        Also, time for you to GROW UP

        • Avatar


          Sunday, January 24, 2021 at 4:18 pm

          Please don’t come here. We need people who understand the benefits of behaving for the common-good. Not self centered, selfish people, who think only about themselves.

      • Avatar


        Saturday, January 23, 2021 at 10:40 pm

        Isaan John you a rude and ignorant person. Maybe have headache drinking home brew whisky all day

  4. Avatar


    Saturday, January 23, 2021 at 1:07 pm

    The vaccines are not 100% protective and we’ll have to accept that. If by chance you do get COVID, after being vaccinated, it’s supposed to be less severe. In the west we should have most of the population vaccinated, that wants it, by mid-year. Also better anti-virals treatments will be more readily available and we should be able to bring improved testing to market. Developing countries will take longer.

    Once these tools are in place then we’re in a position to manage this situation and we’ll have a new normal that’ll allow us to reopen fully. People will get sick and die just like with the flu but not in the numbers we have today. We won’t be defenseless like we were the past year.

    • Avatar

      Issan John

      Saturday, January 23, 2021 at 2:15 pm

      Agreed, Ben. Thanks for doing the trials for the rest of us – very considerate 🙂

      • Avatar


        Saturday, January 23, 2021 at 10:42 pm

        You very stupid person island John. No say isaan, you insult people from isaan. Isaan persons not stupid like you

      • Avatar


        Sunday, January 24, 2021 at 12:35 am

        I trust the process in place. The trials have occurred. I play the percentages and they’re telling me to move forward and I will. Also I generally tolerate vaccines well and have had them all. Life is full of risks and this is one I’m fully willing to take in about a weeks time.

        There are numerous reasons why this vaccine was developed faster and I’ll list the ones I’m aware of:

        -The technology does not require live virus which is usually grown in eggs and takes time
        -The technology is a platform that you don’t have to rebuild each time from scratch like traditional vaccines
        -The funding for vaccine development and manufacturing was funded up front by governments via advance vaccine purchases and grants. Also entities like the Gates foundation stepped in with funds at critical times to keep the process going. This saved years and freed up everyone to move forward at warp speed. Typically drug and biotech companies provide the funding up front
        -Everyone in the process worked overtime, not regular time. The FDA didn’t take it’s sweet time and probably worked harder than it ever has
        -The studies were more narrow and didn’t answer 10 questions. It answered two so far which is “Will the vaccine keep people from getting sick/severely ill?” and “Is it safe?”. Other questions such as “Will the vaccine prevent spread from the vaccinated?”, “Does it work on kids younger than 16?”, “Is it safe for pregnant women?”, etc. will be answered in time as more studies are conducted. The goal was to stop the illness and death toll.

        I can understand peoples skepticism but it’s usually because of lack of knowledge and/or no tolerance for risk. Everyone has a choice and I expect them to get on board once they see enough of their friends do it without any downside or they see someone they know get severely ill who chose not to vaccinate. If the vaccinated start dropping like flies then I’ll have been wrong but the percentages say that won’t happen.

      • Avatar

        James R

        Sunday, January 24, 2021 at 1:02 am

        Issan John

        You won’t be getting any of our western vaccine, you are in Thailand, you will be getting the Chineses vaccine as the vaccines you have on order from us will not be processed for months yet.

        Or you can come back to England and get two free shots of our vaccine.

        They are safe as my son as a key worker had his first shot three weeks ago, no side affects.

  5. Avatar


    Saturday, January 23, 2021 at 4:16 pm

    it s the same sound in every country, fact is it seem they have no idea if the mass immunity will work as everybody in a world wish. so better to prepare all of us. vaccine campaign just start it will take months before to see the result. the last i read about one vaccine is the dose sold are less efficient than the dose used for the trial…….some going to make money on this. well some said at least one more years before to see a change on the travel restriction, i guess it is reasonable.

  6. Avatar


    Saturday, January 23, 2021 at 6:41 pm

    Issan john you are so against falange coming back to thailand on a daily basis why do you have so much hatred towards the west and the land of freedom and free speech it’s your birth home your such a bitter man towards us shame on you

    • Avatar

      Issan John

      Sunday, January 24, 2021 at 2:40 am

      I’m against “falange” ( ? ) “coming back to thailand” as I see no reason why one person’s life should be put at risk purely so someone else, whatever country they’re from, can enjoy themselves and have a holiday.

      You evidently think that because you’re a “falange” your holiday is more important than other people’s lives. I don’t, so we’ll just have to disagree on that.

      As for the rest, I despise the absolute dregs of my country who’ve contributed nothing to it in any way, never served in the blue light services or the military in any capacity, but who think that nothing more than an accident of birth gives them something to be proud of.

      If the cap fits, wear it.

      I also think my country’s currently being run into the ground by the biggest group of clowns and incompetents to have done so in living memory, and I see no point in trying to pretend otherwise – not that anyone who’s had anything to do with running the UK in the last twenty years did any better, which is about as sad an indictment of any country as it comes.

      That’s not “hatred”, just disappointment.

  7. Avatar

    Udon Man

    Sunday, January 24, 2021 at 6:49 am

    The easiest thing to do is run away. Me thinks British people complain way too much. Have too much self importance and arrogance. If one then runs away from their country what do they do? Still complain. Its in the blood.

  8. Avatar


    Sunday, January 24, 2021 at 5:47 pm

    I was a medic in the British army for 12yrs so yes I’m proud of my country not for who runs it now but because of the good it has given the world over tbe centuries thats why its called Great Britain but no doubt you will come up with the bad things it has done never the good yet you live in a country that has already been run down by the clowns where the government on a daily basis dictates to it’s people allows them no freedom or speech, imprisons people for speaking against them ,Thailand is beautiful just the rot from within that’s killing it

  9. Avatar


    Sunday, January 24, 2021 at 7:40 pm

    Little John despises certain “dregs” yet concluded theres no hatred. Hmmmm. Despise and hate are very closely linked words. Much more so than despise and disapointment. Looking down on anyone confirms lack of empathy and intelligence.

  10. Avatar


    Monday, January 25, 2021 at 5:33 pm

    So many world class medical experts always in the chat And Issaan john at the party as usual.

    Here’s some common sense and a prediction without bothering about the stats, vaccine and all that Crap. The lockdowns and measures will not stop till pretty much all of the population will bend there knee, begging the goverbements to help them because everybody will be financially destroyed, mentally and physically drained and can’t handle the violence and hopelessness any longer.

    This has been predicted 15+ years ago that we wild go into a dystopian world either by a new world war or virus, go figure

  11. Avatar

    js bromley md mph

    Saturday, January 30, 2021 at 4:49 am

    The Phase III trials of the Pfizer and Moderno vaccines were not “laboratory tests,” as asserted by Dr Young, they were clinical trials involving tens of thousands of subjects. The reduction in risk of acquiring COVID-19 illness in those large trials was 94-95%; the reduction in risk of acquiring serious illness (requiring hospitalization) was 100% (in other words, no vaccinated subject in the large trials became seriously ill). These are empirically observed data, they do no require extrapolation from “laboratory tests,” and it is very unlikely that efficacy will drop to 80%.
    Herd immunity is not a hypothetical, it is a phenomenon which has been observed in many scenarios over the last two centuries. With COVID-19 once 60-70% of a local population have acquired immunity by either infection or vaccination, herd immunity is acquired. This is not unsubstantiated guesswork, it is the application of basic principles of epidemiology. For anyone living in a place where 60+% of the population has either been already infected or vaccinated, the risk of catching COVID-19 is very low.
    COVID-19 is now thought to have a case fatality risk of 0.1-0.2%, which is essentially the same as influenza. In other words, 1 to 2 people of every 1000 who catch COVID-19 will die, the large majority of those being patients with serious pre-existing illness or very advanced age. For anyone who does not have severe chronic illness and is not over about 70 years of age, the risk of severe illness or death from COVID-19 is very low.
    These facts are independent of politics, culture, or national origin. In Sweden, where herd immunity appears to have been achieved, the current incidence of fatality from COVID-19 is 1 per million per day. In other words, 1 person out of each million residents of Sweden dies with COVID-19 each day, and that incidence is dropping toward zero. To put this in context, around the world about 20 people out of each million die every day from all causes: those 20 deaths per million per day took place before SARS-CoV-2 emerged, and those 20 deaths per million per day will continue long after all of us have forgotten about COVID-19.

Leave a Reply

Your email address will not be published. Required fields are marked *

Follow Thaiger by email:

Best of8 hours ago

Top 5 Wine Bars in Bangkok with Delivery

Best of9 hours ago

The Best Bakeries in Bangkok with Delivery

Coronavirus (Covid-19)9 hours ago

More Pattaya people arrested drinking alcohol, violating Covid measures

Welcome back to Thailand!

Thaiger is getting behind local businesses for the restart of tourism in Thailand - up to 50% discounts across all advertising packages!

Best of9 hours ago

5 of the most appealing Phang Nga hotels

Phuket10 hours ago

“Phuket Sandbox” still on, provincial restrictions set after uptick in Covid-19

Thailand11 hours ago

Thailand News Today | Boss indictment, Pattaya arrests, bubble burst | July 27

Join the conversation on the Thaiger Talk forums today!
Best of11 hours ago

Top 5 bars in Pattaya

Thailand11 hours ago

UPDATE: Dying Samut Prakan mother tells daughters to go to orphanage

Best of11 hours ago

Top 5 Thai restaurants in Krabi

Drugs12 hours ago

Hong Kong officials seize 61 kilograms of heroin shipped from Bangkok

Best of12 hours ago

Koh Pha Ngan’s 5 best resorts

North East12 hours ago

Couple “drops off” Covid infected 80 year old father at Korat temple, drive off

Coronavirus (Covid-19)12 hours ago

Phuket officials add new layers of restrictions, Central closed for 7 days

Thailand13 hours ago

Korat construction camp closed following Covid outbreak

Coronavirus (Covid-19)14 hours ago

Tuesday Covid Update: 14,150 new cases; provincial totals

Thailand5 months ago

Thailand News Today | Thai Airways in rehab, All go for Songkran | March 4

Tourism5 months ago

Phuket’s nightlife. Yes, bars and clubs are still open | VIDEO

Phuket5 months ago

Thailand News Today | Covid passport talks, Thai Airways heads to court | March 2

Tourism5 months ago

Phuket Thai food treats you need to try | VIDEO

Thailand5 months ago

Thailand News Today | Bars, pubs and restaurants ‘sort of’ back to normal | Feb 23

Tourism5 months ago

In search of Cat & Dog Cafés in Phuket Town | VIDEO

Thailand6 months ago

Thailand News Today | Gambling crackdown, Seafood market to reopen, Vlogger challenge | Jan 21

Thailand6 months ago

Thailand News Today | Covid testing for visas, Business impact, Vaccine approval | January 19

Thailand6 months ago

Thailand News Today | Weekend Bangkok bombs, Thailand fires, Covid update | January 18

Thailand6 months ago

Thailand News Today | Stray car on runway, Indonesian quake, 300 baht tourist fee | January 15

Thailand6 months ago

Thailand News Today | Governor off respirator, sex-trafficking arrest, condo prices falling | January 14

Thailand7 months ago

Thailand News Today | Chinese vaccine, Thailand ‘drug hub’, Covid update | January 13

Thailand7 months ago

Thailand News Today | Bangkok may ease restrictions, Phuket bar curfew, Vaccine roll out | January 12

Thailand7 months ago

Thailand News Today | Covid latest, Cockfights closed down, Bryde’s Whale beached | January 11

Thailand7 months ago

Thailand News Today | Southern floods, Face mask fines, Thai Air Asia woes | January 8