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You test positive for COVID-19 Now what?

You test positive for COVID-19. Now what?

With the number of COVID-19 cases rising across the country, it is more likely than ever that we have either interacted with or know of a person who has been tested positive for COVID-19. And if we’re feeling a little temperature or a sore throat, our next thought tends to be “Should I take a PCR test?”. With the amount of ambiguity and daily change of regulations, we, at oDoc, want to keep you informed and updated with the latest news regarding COVID-19 processes in Sri Lanka.

This is the latest information on quarantine centers and discharge policies at the time of writing.

If tested positive for COVID-19, you will be placed in a hospital or an intermediate care center (ICC) depending on how severe your symptoms are. If you’ve tested positive at a private lab, the lab is obligated to inform the Ministry of Health and local PHIs of your positive test result and they will decide on your place of quarantine. There are options to stay in a government care center for free or a private care center for a fee.

In order to reduce the strain on hospitals, the option of home quarantine could be available soon but this process has not been finalized yet. Local PHIs would need to keep a close check and advise on health guidelines to asymptomatic patients who are undergoing a home quarantine.

Private care centers include:

  • Club Koggala Village – Managed by Sri Lanka Army
    • Daily room rates range from LKR 12,000 to LKR 25,000
    • Full Board meals
    • Room confirmation subject to availability and final approval by government authorities
    • Contact information: 0773124521/0772092084
  • The Beach Cabanas Retreat and Spa – Managed by Sri Lanka Army
    • Daily room rates range from LKR 15,000 to LKR 29,000
    • Full Board meals
    • Room confirmation subject to availability and final approval by government authorities
    • Contact information: 0773124521/0772092084
  • Mirage Hotel Colombo – Managed by Nawaloka Hospitals PLC
    • Daily room rates range from LKR 17,000 to LKR 22,000
    • 24 hour medical support
    • Full board meals
    • Contact information:
      • Hotline: 0770066006/0760089740
      • Email:
  • Siddhalepa Anarva Hotel, Mount Lavinia – Managed by Asiri Health
    • Daily room rates range from LKR 17,000 to LKR 22,000
    • 24 hour medical support
    • Full board meals
    • Contact information:
  • Jetwing Beach Hotel, Negombo – Managed by Ninewells Hospitals
    • Daily room rates range from LKR 17,000 to LKR 25,000
    • 24 hour in-house medical care and ambulance on standby
    • Full board meals
    • Contact information:
      • Hotline: +94 11 204 9900
      • Website:

The latest update from Chief Epidemiologist, Dr. Sudath Samaraweera, regarding the length of quarantine and discharge policy is as follows:

  • If you are positive for COVID but don’t show any symptoms and are not in a high-risk category, you will be sent to an ICC. You will be discharged from this center after 10 days and will be required to home quarantine for 4 days.
  • If you are positive but show mild to moderate symptoms and are not in a high-risk category, you will be sent to an ICC. You will be discharged from this center after 14 days.
  • If you are positive with severe symptoms, you will be sent to a COVID-19 hospital and will be kept there for 3 weeks or more depending on how severe the symptoms get. You will only be discharged after a negative RT-PCR test.
  • If you have been placed in a quarantine center through contact tracing after a close associate of yours was tested positive for COVID-19, you will need to remain in quarantine for 14 days. You will only be discharged if you test negative on a RT-PCR test.

We will continue to update this article if and when regulations change so keep checking this space for any COVID-19 related news in Sri Lanka.

If you would like to read more about vaccines, especially the vaccine rollout in Sri Lanka. Check out this article

Read our previous blog on Do the vaccines actually work?


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200 million doses later: How have the vaccines fared in the real world?

Busting Myths: Part 4

200 million doses later: How have the vaccines fared in the real world?

By now, most of us have received a link to register for Sri Lanka’s mass COVID19 vaccination rollout. Whilst some of us have jumped on board, others may still be trying to decide. However, given the rumours and misinformation that are rife in society, we wanted to help our public make the most informed decision about vaccines.

In the fourth post of this blog series, we break down the results from the 200 million doses given around the world to decide whether these rumours have legs or are just misinformation.

Global vaccine roll out

Globally, 200 million doses of AstraZeneca, Moderna and Pfizer/BioNtech vaccines have been administered. Some countries like Israel have raced ahead (vaccinating 71 out of every 100 people ) whilst others haven’t even started yet.

Correlation does not mean causation

Media attention on these rollouts combined with social media have resulted in  widespread rumours about serious side effects or deaths due to vaccines. But what are the facts? We are talking millions of vaccinations. So even if the vaccines have a tiny 0.00009% likelihood of a severe adverse event (death or serious side effects like anaphylaxis) when the numbers inoculated are in the millions, we are bound to see one or two cases crop up. Before the agencies can investigate the event, the media publicises the cases for sensationalism without thorough fact-checking or scientific examination. The WhatsApp sharing mill goes into overdrive. What do we miss? The important principle that correlation does not mean causation.

Let us explain: Say ice cream sales increased in a certain small town, but the rate of drowning deaths in that town also increased sharply. Therefore we decide that consumption of ice cream causes drowning.

Dr Bownstein of Boston Children’s Hospital succinctly states(2) “We have to be very careful about causality,” Brownstein said. “There are going to be spurious relationships, especially as the vaccine is targeting the elderly or those with chronic conditions. Just because these events happen in proximity to the vaccine does not mean the vaccine caused these events.”

The critical question is: are these events happening at a greater rate in the vaccinated population than in the average population? To answer this question, agencies around the world investigate each event to decide what caused it.

Is anyone monitoring these vaccine drives?

The major regulatory agencies closely monitor the vaccine rollouts in each country. Before injecting a patient, vaccine centres must speak to patients and check for reasons to not inject the vaccine. Vaccine locations must also be prepared and stock supplies to treat and manage severe adverse effects like anaphylaxis.

Once someone is vaccinated in the UK, they need to stay at the location for 15 minutes to be monitored for immediate adverse reactions. The NHS uses technology for primary care providers to log all data related to each vaccination. All reactions have to be reported to the Medicines and Healthcare products Regulatory Agency (MHRA) which is then investigated. Deaths of any person who has been vaccinated are reported and investigated by the MHRA, including via post-mortem(3).

Similarly, the US CDC runs a Vaccine Adverse Event Reporting System (VAERS) which closely monitors post-vaccination adverse reactions. Since the immunisation drive began in the US in December 2020 up till January 3rd 2021, the CDC reports that 4,393 or 0.2% of the 1.8m doses administered have reported adverse reactions.  Only 175 cases or 0.00009% were marked as potential severe adverse reactions for further investigation. Twenty-one of these cases were anaphylaxis which began around 13 minutes post-vaccine administration with all recovering and being discharged(4). The remainder were classified as non-serious (rash, itchy throat, mild respiratory symptoms).

But what about long term side effects?

We covered side effects extensively in our article about vaccine safety with most side effects including fever, fatigue, chills, body ache that lasts one to three days on average. 

Once the vaccine ingredients do their job – aka present the spike proteins to the immune system so it can ramp up a response – the ingredients disintegrate or are broken down by that immune response. They don’t hang around in the body. 

Ultimately, it is difficult to say what’ll happen in 30 years but vaccine side effects are known to happen immediately and in the short term not years later. This comes from the experience of having vaccines for 24 diseases, most of which are part of Sri Lanka’s mandatory vaccination programs for decades. Also good to note that most of those vaccine trials had less enrollments than the COVID vaccine trials. 

The real risk-benefit toss up is between what appears to be a safe and effective vaccine or a deadly, unpredictable disease.

What’s happening in Israel & South Africa?

People’s hesitancy to sign up for vaccinations may be linked to partial information reported about Israel & South Africa.

Let’s look at Israel first:

Since December 19th 2020, Israel has vaccinated almost 71 out of 100 people with Pfizer/BioNTech. Priority was given to the over 60+ age group, the immunocompromised & the healthcare workers. This widespread vaccination can help scientists further validate the accuracy of the clinical trial data. Maccabi, Israel’s healthcare system, states that only 28 of the 128,600 with two doses have contracted COVID19. 

However, at the same time, it appears that Israel began its third and largest peak in deaths(5) leading to its third lockdown on January 6th. So what does that mean?

Short answer In layman’s terms: correlation does not mean causation. The overlap in time of the vaccine rollout and the increase in deaths does not mean vaccines caused deaths. It may be because deaths lag infections. The data shows less moderate to severe cases this time around than in the previous lockdown in Israel meaning that vaccines are probably helping people not fall sick!

Want more details? Read on:

Case reports suggest a trend that COVID deaths lag infections by 3-6 weeks. The spike in fatalities between December 11th and January 26th is possibly related to infections between 26th November-5th January, assuming the lower end of the lag range. The 7-day moving average of confirmed cases just before the 2nd and 3rd Israeli lockdowns look the same about three weeks before lockdown. 

Most importantly, the number of new moderate and severe cases in the 60+ population peaked six days after the third lockdown vs 14 days after the 2nd lockdown. This earlier peak & subsequent decline is attributed to the vaccines(6).

Next, South Africa, UK & Variants:

2021 has brought great news in terms of vaccines. Still, it has also resulted in the news of variants or mutations in the Sars-Cov-2 virus that makes it more infectious. The big question has been how do the vaccines stack up against these variants?

Alongside the British/Kent variant (B., we now see news of a highly infectious South African variant (B.1.351). There is no evidence that the South African strain causes more severe illness; however, more infectious means more people infected, more severe disease, and more deaths. The South African variant’s main issue is a mutation that may allow it to dodge the immune system and render the vaccines ineffective. 

As always, scientists look to prove their beliefs by conducting studies. An early study (not peer-reviewed) tested the Pfizer vaccine in the lab and have found it less effective(7). Whilst Moderna’s seem to hold up, in a 1,700 person Astrazeneca early study has shown to have “minimal” or 22% protection against mild and moderate disease caused by this specific variant(8). However, this trial was conducted on an average age group of 31 and so wasn’t created to find the efficacy on the severe disease. 

However having more vaccines is now proving to be better. NovaVax, another two dose US vaccine, was found to be 95.6% effective against the original variant, 85.6% against the UK variant and 60% against the South African variant in trials.The trials against the new variants are still ongoing. 

All vaccine manufacturers are working on conducting trials and creating boosters against the variants to improve effectiveness.

Finally, want to take the vaccines but have allergies?

Both The UK MHRA and the US CDC have recommended persons with histories of severe allergic reactions unrelated to vaccines or injectable medications to get vaccinated. 

However, those with allergies to polyethylene glycol (PEG) or polysorbate are recommended not to get the mRNA vaccines. Furthermore, the MHRA recommends not to get vaccinated only if you have a known allergy to a component of the vaccines. 

Please see the links below for ingredients of each vaccine:

To summarise, major agencies have recommended that the public get vaccinated. Only those who have known allergies to the vaccine ingredients do not get vaccinated.

How to weigh up the risk-benefits?

COVID19 has caused 2.4million deaths around the world(1) and over 400 deaths in Sri Lanka. One hundred six million people have been infected with the virus, which affects the lungs and multiple organs like the brain, heart, and kidneys, to name a few. Long COVID is a condition present in many “recovered” COVID patients. They experience fatigue, muscle weakness or body aches even six months post asymptomatic to severe illness. 

Vaccines undergo rigorous clinical trials, the data reviewed by multiple panels of experts & regulators searching for efficacy and safety data. Adverse events are most likely to occur soon after vaccine administration. With over 128 million doses being administered, there have been less than 0.005% reports of severe adverse reactions. Furthermore, the vaccine ingredients disintegrate and leave your body after 1-2 days.

To put simply, COVID19 causes a more considerable risk of death and illness than the vaccines. Suppose we want to achieve herd immunity and return to economic activity (or go on holiday to our favourite locations) sooner than later. In that case, we believe it is most prudent to take both the doses of the vaccine that will be soon made available to you.



  1. Bloomberg COVID19 Vaccine tracker
  2. Dr. Widmer (2021) Fact-check: No link between COVID-19 vaccines and those who die after receiving them. ABC News.
  3. Primary Care Pharmacy Network., Delivery of COVID Vaccination Services (2020)
  4. Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine — United States, CDC, December 14–23, 2020
  5. COVID19 tracker, Google
  6. De-Leon, A et al., (2021) First indication of the effect of COVID-19 vaccinations on the course of the outbreak in Israel. Preprint. MedXRiv.
  7. Xie, X et al (2021) Neutralization of SARS-CoV-2 spike 69/70 deletion, E484K, and N501Y variants by BNT162b2 vaccine-elicited sera. Preprint. BiorXiV.
  8. Oxford/AstraZeneca jab fails to prevent mild and moderate Covid from S African strain, study shows. Financial Times, Feb 2021
  9. Pfizer-BioNTech (2020).,Vaccines and Related Biological Products Advisory Committee Meeting., FDA Briefing Document.
  10. Moderna (2020).,Vaccines and Related Biological Products Advisory Committee Meeting., FDA Briefing Document.
  11. Information for UK recipients on COVID 19 Vaccine AstraZeneca, MHRA

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Vaccine safety: Three (scientific) reasons why they are safe

Busting Myths: Part 3

Vaccine safety: Three (scientific) reasons why they are safe

With the impending mass COVID19 vaccination rollout in Sri Lanka, there are murmurs about vaccines causing allergic reactions or even deaths. It was only with its mass vaccination programs that Sri Lanka could eradicate diseases like measles or polio. It remains integral to economic recovery that there is public buy-in for a COVID19 vaccination scheme.

To that end, we break down the results from the clinical trials to see whether these rumours have legs or are just in fact, misinformation.

Clinical Trials

Scientists design clinical trials to get enough data to decide whether vaccines are safe and effective for people. They seek to accurately find whether severe adverse events (e.g. allergies, deaths etc.) occur after people receive the vaccines. If adverse reactions occur, trials are paused, and safety data are reviewed by a board consisting of independent experts and international regulators. The trial’s integrity is of utmost importance; therefore, safety reviews are taken seriously. Sometimes, trials can be halted for months until a decision is reached. The safety board decides whether the adverse reaction was due to the vaccine or coincidental – and if due to the vaccine, whether the case is an outlier or requires the trial to stop.

In September 2020, AstraZeneca paused its 30,000 volunteer study(1) as one person developed a suspected adverse reaction. No further doses of the vaccine were given whilst a safety board reviewed the data to determine whether the vaccine caused the reaction. After review, the board confirmed the trial was safe and gave the green light for it to resume(2).

How effective are these vaccines? Little recap from Part 1 of our Blog Series

Clinical trial data has shown that all of the vaccines authorised so far are very effective at preventing symptomatic illness. The table below gives a quick summary of the findings so far:

Importantly ALL the vaccines have 80%+ efficacy against preventing severe disease and 100% against deaths & hospitalisation. After 2.3million deaths around the world, this is welcome news.

1) The trials have 30-40,000 people each to mimic real-world conditions.

Phase III clinical trials are the most extensive, most time consuming and most expensive part of the development process. Scientists look to mimic real-world conditions (different ages, genders, cities etc.). They aim to see whether the vaccine effectively protects against the virus AND whether it causes any side effects in the wider population. 

AstraZeneca & Moderna enrolled 30,000 people each in their Phase III, Pfizer/BioNTech 42,000, Novavax 20,000 and Russia’s Sputnik 21,000. In comparison, the GlaxoSmithKline MMR vaccine Phase III trial only enrolled 5,000 participants and is now a widely accepted part of the Sri Lankan immunisation strategy(3)

Sample sizes are large to reduce “sampling error”. Sampling error is the difference between the sampled results and the population’s results if the sample doesn’t represent the population accurately. By enrolling tens of thousands of people – each of these vaccine trials could reduce sampling error and thus be as accurate as possible in their data collection.

2) The trials showed mild reactions in mostly younger people which lasted a median of one day.

Every vaccine trial looks for occurrences of “local” (at the site of injection) and “systemic” (around the body) reactions to the vaccine. Local reactions include injection site pain, redness, swelling. Systemic adverse reactions include fever, fatigue, headache, chills, vomiting, diarrhoea, muscle or joint pain. If reactions occur, they happen within 1-2 days of getting the vaccine and last an average of one day. 

AstraZeneca separated its participants into three age groups: 18-55, 56-69, and 70+. In the table below, we can see which local and systemic reactions occurred in the study participants and how long they lasted. 

They were more common in the 18-55 age group with most complaints of fatigue, headache and muscle ache soon after getting the vaccine. For all age groups and all complaints, the reactions disappeared in a few days(4).

Pfizer/BioNTech saw younger people experiencing local and systemic adverse reactions more often and in greater intensity than the older age groups. They often felt pain at the injection site at a greater intensity than the older participants. Both groups complained of fatigue, headache and body aches. 

All of Moderna’s participants complained of local reactions with pain & temporary swelling of lymph nodes being the most common. However, most reactions only lasted 1 to 2 days. Fatigue was the most commonly reported systemic reaction followed by headaches, body ache, fever and chills for 1-2 days post-vaccination.

3) The vaccines rarely caused severe adverse reactions and showed to be 100% protection against death.

As Phase III is designed to mimic the real population, events such as deaths or heart attacks that will typically occur in the real population also occur in the trial groups. The safety boards’ responsibility is to review the data to decide which events were caused by the vaccine and which occurred naturally. For this, they look at rates of these events in the general population by age group and deep dive into each case’s particulars. 

None of the vaccine trials (including Russia’s Sputnik) has had a severe adverse effect resulting in death as a result of the vaccines (5)(6). Of the 84 severe adverse events (in 11,000 candidates) reported by AstraZeneca, only one classified as possibly related to the vaccine(4). This one case is 0.000085% of the total study population, a tiny percentage. 

All of the vaccines peer-reviewed so far shows to have 100% efficacy against death & hospitalisation.

Weighing up the benefits

COVID19 has caused 2.3million deaths around the world(8) and over 300 deaths in Sri Lanka. None of the COVID19 vaccines reviewed thus far has yet had a death determined to result from the vaccine. Adverse events are most likely to occur soon after vaccine administration. With over 128 million doses being administered globally, there have been less than 0.005% reports of severe adverse reactions. 

The choice is between contracting a virus known to cause lasting damage to the body (if not death) and taking a vaccine that is found to prevent death 100% of the time. Moreover, the vaccines reviewed thus far are not known to cause severe adverse events; the winner becomes abundantly clear. 

We would urge the Sri Lankan public to accept the AstraZeneca or Pfizer vaccines.

Read our previous blog on Do the vaccines actually work?



  1. AstraZeneca Press Release (Sept 20) Statement on AstraZeneca Oxford SARS-CoV-2 vaccine, AZD1222, COVID-19 vaccine trials temporary pause.
  2. AstraZeneca Press Release, (Sept 20) COVID-19 vaccine AZD1222 clinical trials resumed in the UK.
  3. GlaxoSmithKline (2012) Consistency Study of GlaxoSmithKline (GSK) Biologicals’ MMR Vaccine (209762) (Priorix) Comparing Immunogenicity and Safety to Merck & Co., Inc.’s MMR Vaccine (M-M-R II), in Children 12 to 15 Months of Age. Clinical
  4. Ramasamy et al (2020)., Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial. The Lancet 396: 1979-1993.
  5. Voysey et al (2020), Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. The Lancet 399: 99-111.
  6. Pfizer-BioNTech (2020).,Vaccines and Related Biological Products Advisory Committee Meeting., FDA Briefing Document.
  7. Moderna (2020).,Vaccines and Related Biological Products Advisory Committee Meeting., FDA Briefing Document.
  8. Logunov. D et al (2021)., Safety and efficacy of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine: an interim analysis of a randomised controlled phase 3 trial in Russia. The Lancet. Online first.
  9. Bloomberg COVID19 Vaccine tracker
  10. Dr. Widmer (2021) Fact-check: No link between COVID-19 vaccines and those who die after receiving them. ABC News.
  11. Primary Care Pharmacy Network., Delivery of COVID Vaccination Services (2020)
  12. Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine — United States, CDC, December 14–23, 2020
  13. COVID19 Vaccines and Allergic Reactions, CDC, January 2021
  15. Information for UK recipients on COVID 19 Vaccine AstraZeneca, MHRA

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Do the vaccines actually work?

Do the vaccines actually work?

Short answer: Yes they do and the results are available in the detailed Phase III trial data produced by the three companies in the last two months.

Long answer: Moderna & Pfizer/BioNtech vaccines have similar efficacy whilst AstraZeneca has less efficacy but pricing & storage/effective delivery becomes an important factor in deciding which vaccine is best for which country.

Click here our previous blog on Busting the Vaccine Myths


A two dose vaccine with the second dose to be administered 28 days after the first dose. Study data showed a 95% efficacy rate 7 days after the second dose with efficacy in adults over age of 65 at an excellent 94%. The final analysis was to be done at 164 case mark but instead they were able to surpass and hit the 170 case mark (due to the prevalence of COVID19). 170 people enrolled in the trial contracted COVID19 – when called back, it turns out 162 were from the placebo arm compared to 8 in the vaccine arm.

Approved by the FDA and the EU for emergency use, Pfizer/BioNtech vaccine has been deployed since early December in countries across the world. Due to the sensitivity of the mRNA vaccine compound, the vaccine requires storage at -70C to prevent denaturing of the key compound and rendering the vaccine vials useless. As such, cold storage supply chains are being developed around the world to safeguard against denaturation in transit. Given the freezing temperatures required, the costs associated with deep freeze supply chain equipment and the precision with which the vaccine must be administered post vial opening, this particular vaccine deployment may be difficult to execute in south asian countries such as Sri Lanka.


Another two dose vaccine with the second dose administered 28 days after the first. Data showed a 94.1% efficacy rate 7 days after the second dose. Final analysis happened at the 196 case mark with 185 cases in the placebo group and 11 in the vaccine group. Interestingly, the analysis included 30 severe cases of COVID19 – all of which were in the placebo group and none in the vaccine group heralding this vaccine as better at preventing severe outcomes of the disease.

The vaccine can be stored at -20C (normal refrigeration temperatures) for upto six months making them more friendlier to tropical countries and eliminating the heavy investment into logistics that may be required of Pfizer/BioNtech. Given the novel nature of the mRNA vaccines, those who administer the vaccine need to work in a timely and efficient manner to avoid wastage and may require upskilling of existing healthcare staff to ensure the same.


Earlier created to be a two dose vaccine, a mistake during one part of the trial resulted in a surprising finding that administering half a dose first and then a full dose second resulted in 90% efficacy vs. 62% efficacy in those getting the two full doses. However, only 2,700 persons were administered the “mistaken” dosage and this requires further study. This leaves AstraZeneca as the vaccine candidate with the least efficacy when compared to the two mRNA vaccine options. Results were based on a 131 case mark with 30 in the control group and 11 in the vaccine group contracting the virus.

AstraZeneca remains the cheapest vaccine at GBP 3/dose and can be stored at room temperature (like most other existing vaccines) allowing health workers to work in a familiar setting.

If you are questioning which vaccine should you take: given what is known of COVID19 (its rapid spread, its attack on the respiratory and vascular systems of the body, long COVID afflicting patients six months post initial recovery and the fatality rate), all of these vaccines appear as attractive alternate options.


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Vaccines: Busting the myths and laying out the science

Vaccines: Busting the myths and laying out the science

Close to a year into the pandemic, vaccines seem to be on everyone’s mind. It is nothing short of a tremendous feat that we now have not just one but three approved vaccine candidates either already deployed or preparing to be deployed around the world. Taking into context the standard vaccine (or drug) development timeline of ca. 5-10 years, it speaks to the brilliant abilities of scientists when able to work singularly towards one goal, have the funding available and the political will in place for science to succeed.
However this dichotomy of the “usual” vaccine timeframe and the 10 month COVID19 vaccine development timeframe has resulted in some murmurs of mistrust in certain sections of society across the world. Furthermore, the advent of the mRNA vaccines and the novel technology associated with it compared to previous vaccine platforms have also contributed to the same. Vaccines are the predominant method by which we can tackle this pandemic which is now stepping into its 2nd year. If we are to have any hope of getting back to a “normalcy” and saving millions of lives, widespread immunity through vaccine inoculation is essential. As such, we at oDoc have prepared a short primer to address your most pressing questions about the COVID19 vaccines currently available.

Part 1: were the vaccines rushed?

Short answer: no safety steps were cut.

Long answer: The drug development process is made up of several steps: 1) a preclinical trial 2) a clinical trial which is broken down into a) Phase I b) Phase II and c) Phase III.

Preclinical stage is about deciding on the desired effect of the drug and getting initial information on its efficacy and safety. The vaccine candidate is tested inside test tubes (in vitro) and in animals (in vivo). Of 100 drugs tested usually only about 32 moves to the next stage. That’s a high level of failure so it’s often hard to find financing for this phase.

The three phases of the clinical stage have different objectives. Phase 1 is about assessing the safety and tolerability of the drug in a small group of healthy people (usually has a 75.1% success rate). Phase 2 is designed to test efficacy of the drug and continue safety testing in a larger group of people (this has a 50% success rate). 

Finally, Phase 3 which follows the gold standard format of trials, the randomised control trial with a large group of volunteers (ca. A few thousands usually but in the 40-50,000 range for the COVID19 vaccines) split into a placebo or control group and the vaccine candidate group. These trials are expensive, time consuming and difficult to run and aim to evaluate the risk-benefit of the drug across a cross section of the target population. 

None of these steps were cut for any of the COVID19 vaccines. As it’s a pandemic and this disease is everywhere and because there is political & economic will to develop a vaccine – there were plenty of volunteers ready to be enrolled into trials and plenty of funds ready to be invested into the process. Both of which resulted in a rapid development process and enabled the deployment of the vaccines for emergency use as early as January 2021. If anything, we can be encouraged that if the money & interest were there, science could move much faster than it currently does.

Part 2, do the vaccines work and are they safe?

Short answer: Detailed studies taking place over ca. 9-10 months have shown them to be safe and effective in the fight against COVID19. Not only did the authorised vaccines reduce the chance of falling sick from COVID19 but they all seem to prevent death and hospitalisation! 

Important to note that none of the vaccines injects COVID19 into the body. No major reactions were seen in the trials since April 2020 or in the 200 million vaccinations made in the real world since December 2020. Minor side effects from vaccines occur very soon after vaccinations, these include injection site pain, fever, chills and end after a few days. We cover these extensively in our articles Three Reasons Why Vaccines are Safe and 200 Million Doses Later, How Have the Vaccines Fared in the Real World.

Long answer:


The Oxford vaccine (as it’s commonly referred to) is an adenovirus based vaccine however it was earlier developed and tested for a variety of diseases including on Ebola (2014) and Zika (2016). Those trials weren’t successful at fighting disease but helped researchers test the safety of the vaccine. 

ChAdOx1 was then adapted to COVID19, early clinical trials had safety issues and moved to Phase I trials in early April. Phase II/III trials began in August in four countries: UK, Brazil and South Africa and final results were published in November. In total, ca. 23,000 participants were enrolled in the study. 

AstraZeneca is a 2 dose vaccine, given 28 days apart but now studies show that a 12 week break may increase vaccine effectiveness. The vaccine provides 76% protection after 1st dose, and 82% after 2nd dose (with a 12 week break). It’s shown to prevent deaths and hospitalisation by 100% and even may lower the chance of you infecting other people! Furthermore, it can be stored at normal fridge temperatures making handling it easier for those of us in the tropics. 

Against the UK variant, this vaccine shows 71.4% efficacy after two doses but against the more infectious South African variant, it’s down to 22% (albeit not a large and varied trial).


As mRNA technology is highly customisable, BioNtech developed 20 candidates for early stage research as soon as Chinese laboratories released the genetic sequences of Sars-Cov-2 in Jan 2020. 

As shown in the timeline below, they then teamed up with Pfizer and began Phase I and II trials simultaneously. The results were reviewed by the FDA, it then moved the best performer to Phase II / III trials  enrolling 44,000 people across US, Germany, Turkey, South Africa and Brazil. They then met the objective in November 2020 and conducted safety and efficacy assessments on over 38,000 people that took part in the trials. 

Pfizer/BioNTech is a 2 dose vaccine, given 28 days apart and is shown to reduce the chance of getting sick from COVID19 by 94% (i.e. vaccine efficacy is 94% after 2nd dose). It needs to be stored at -70C making it an expensive and difficult option for tropical countries such as Sri Lanka.


The Moderna vaccine, mRNA-1273, is also based on mRNA technology. The short list of vaccine candidates was ready to enter into the research process by January 16th, an amazing 2 days after the Chinese laboratory released the genetic sequence but long before the first cases were detected in the US. Phase I trials began in mid-March with Phase II & III running concurrently from end July with 30,000 participants in the US. 

Moderna is also a 2 dose vaccine, given 28 days apart, reducing the chance of developing COVID19 symptoms by 94%. It also requires cold storage but around -20C which makes it the better mRNA vaccine for Sri Lanka. 


This vaccine, NVX-CoV2373 is also 2 doses (beginning to sound familiar) 28 days apart however this is a protein subunit vaccine. That means it injects a lab made version of the outer shell (spike proteins) of the Sars-CoV-2 virus. This vaccine method is used in existing vaccines like the flu vaccines, HPV and Hepatitis B vaccines. Novavax Phase 3 trials spanned multiple countries and enrolled 30,000 people – none of whom had a serious reaction to the vaccine. 

Its UK trial showed that its 89.3% effective at preventing COVID19 symptoms and its South African trial showed a 60% reduced risk against the South African variant. The Novavax vaccine is another suitable candidate for Sri Lanka given its ability to be stored at 2 to 8C. 

Part 4: Do the vaccines alter my DNA?

Short answer: None of the vaccines alter your DNA. mRNA doesn’t hang around in your body for long and disintegrates after a certain short time period and as such are safer than traditional vaccines. The four main vaccines discussed here only allows your body to recreate the outer shell of the virus (a dummy version!) so your body can arm itself against it. When the real thing comes, the body is able to attack it faster now that it knows what the dummy looks like. 

Long answer: The aim of a vaccine is to teach the body how to recognise the virus. When a virus infects you, it enters into your cells and uses your cells to create more versions of itself. If your immune system can’t catch it early, all havoc breaks loose. Vaccines just give your immune system a blueprint of what to expect so it can prepare itself. 

  • None of the vaccines carries the entire viral structure. Much like our blueprint is our DNA, the virus blueprint is its DNA or RNA. We simply recreate an artificial part of this blueprint to help the body build the outer shell of the virus (or the spike proteins). Human equivalent would be to use your DNA to only recreate your skin. 

  • mRNA creates proteins, it doesn’t create DNA. When mRNA vaccines enter your cells, it releases the mRNA. The mRNA does not enter into the nucleus where your DNA is hosted. Helpers called ribosomes come alongside the mRNA strands and like construction workers laying brick after brick following an architect’s blueprint – starts to assemble the spike proteins or dummy outer shell of the virus. 

  • The spike proteins do not cause any harm on their own because they don’t have the ability to replicate. That ability lies within the virus’ RNA or DNA and we didn’t recreate that. The spike proteins are sent to the cell surface and held out (like waving a flag from a window) or released into the bloodstream. 

  • Vaccines help our immune system arm up against a potential intruder. Our immune system recognises Sars-Cov-2 via the spike protein. By sending some “placebo” spike proteins we give them an early chance to get prepared. Immune cells are usually patrolling around looking for potential intruders. When these sentries come across the spike proteins, they launch an immune response. 

  • All four vaccines activate both arms of our immune system: the innate and acquired arm. Once the immune system recognises the intruder, it will start to create antibodies to fight against it and more importantly, activate memory cells that will remember this knowledge for a time period. 

Want to know if the vaccines are safe? Read the next blog! 


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