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So, can we mix and match vaccines?

So, can we mix and match vaccines?

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As the first dose recipients of the AstraZeneca vaccine started to reach the 12-week mark in May, a lot of people were dismayed that they wouldn’t be able to receive the second jab in a timely manner. A lot of conversations began to revolve around “well, what happens to my immunity?” or “can’t we use another vaccine as a second dose?” and at the time, there weren’t much scientifically sound answers to ease people’s nerves. 

The dearth of the second jab of AstraZeneca vaccine for over 500,000 in Colombo was largely due to the Indian COVID surge shutting down Serum Institute exports in late March. As India hurried to absorb all its domestic production to stop a calamitous third wave, a large number of developing countries, including ours, were left without a way forward. 

In December, Russia & the UK began a study of the safety & efficacy of following up a first AstraZeneca dose with a Sputnik booster and in the UK & Spain, researchers started studying the effects of a follow-up Pfizer booster.

Short answer: The jury is still out on exact findings but some preliminary data is available: side effects were more pronounced in intensity (however not severe and no hospitalisations) and higher antibody levels were seen after a Pfizer booster. 

Want more details? Read on: 

What do we know about safety?

In a UK trial, of the ca. 460 people (median age of 50+ years) that received the AZ jab and then a Pfizer booster 28 days later saw greater intensity in post-second jab side effects than those that received a second AZ dose (“control group”). 

More people felt feverish, had chills, felt fatigued, had joint pain and muscle aches in the study group than in the control group. Most of these effects were felt in the first 48 hours after. Efficacy data has not yet been made available. 

Safety and efficacy data of a booster shot being administered after 84 days is expected in June.

What do we know about efficacy?

A study by the Carlos III Health Institute in Madrid enrolled 663 people who had received the AstraZeneca first dose to receive the Pfizer second dose after eight weeks. The control group did not receive any booster shots. 

The results showed a much stronger immune reaction producing a higher level of antibodies in the Pfizer group than they did with the first dose of AstraZeneca. No severe side effects were reported.

What about a Sputnik booster? 🇷🇺

In December 2020, the UK & Russia began to partner on a study to test safety and efficacy of mixing these two vaccines. On May 28th, Russia announced a hold on it’s mix and match trial with Sputnik as the national ethics committee awaited further data.

What about a Sinopharm booster? 🇨🇳

No data is available at the time of publication however Bahrain has allowed mixing with a second dose of SinoPharm. 

What are other countries doing?

Some countries have already begun allowing a second dose of mRNA to supplement the first dose of another brand. On 1st June, Canada’s National Advisory Committee of Immunization announced it would allow second doses of mRNA to be administered to those that received the first dose of another brand of vaccine. 

Bahrain, Finland, France and Norway had begun allowing second doses of mRNA to be administered to those with AstraZeneca first doses.

What about us in Sri Lanka? 🇱🇰 

The health authorities have not approved the mixing of vaccines in Sri Lanka at the time of publication. The government is attempting to procure the shortfall of AstraZeneca doses by any means possible and has signed an agreement with Pfizer for 900,000 doses for delivery in July. 

The recent crowdings and altercations at AstraZeneca vaccination drives serve to be more harmful than helpful when limiting the spread of COVID19. Until sufficient data is available and vaccines are approved & available for mixing, we believe it’s most prudent for those that received the first AZ dose to adhere to strict COVID19 protocols, limit travel as much as possible and avoid crowded gatherings. 

If you or a loved one have been diagnosed with COVID19 and are awaiting transfer to an intermediate care centre or government facility, oDoc Home Care is available for you. 

With oDoc Home Care, you receive daily calls from a medical doctor for symptom monitoring & medical advice, a wellness bundle including gloves & masks, a pulse oximeter and blood pressure monitors. Click here for more details. 

Sources

  1. Shaw, R., et al (2021) Heterologous prime-boost COVID-19 vaccination: initial reactogenicity data., The Lancet., 397:2043-2046. 
  2. Callaway, E (2021) Mix-and-match COVID vaccines trigger potent immune response, Nature Magazine
  3. Miller, A (2021) Canada recommends mixing and matching AstraZeneca, Pfizer and Moderna COVID-19 vaccines, CBC
  4. Explained: Which are the countries allowing you to mix Covid-19 vaccines?, Indian Express (2021)
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Let’s meet the new vaccines on the block: Sinopharm & Sputnik

Let’s meet the new vaccines on the block: Sinopharm & Sputnik

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With the COVID third wave in Sri Lanka arriving at the same time as the need for the AstraZeneca second jab, there has been some public dismay on the limited supply of Astrazeneca doses. The Serum Institute stopped exporting the vaccine from India after the pandemic tsunami hit its shores in late March. India is now the global epicentre of the pandemic and needs to vaccinate its own population.

What does that mean for countries like ours that were relying on Indian exports?

The Sri Lankan government has procured 15,000 Sputnik and 600,000 SinoPharm doses from Russia & China, respectively in the absence of Indian AstraZeneca supplies. Whilst we await trial data from Germany & Russia on the ability to mix and match vaccines, we take a closer look at these two new vaccines on the block. 

Starting with Russia’s Sputnik 🇷🇺

Since the release of its Phase 3 data in February 2021, Sputnik has been approved by over 60 countries for emergency use. It has not yet received authorisation by the WHO.

What is it? Similar to AstraZeneca, Sputnik is also a two-dose viral vector vaccine. It uses an inactivated virus (usually something like a chimp cold virus) to deliver the Sars-CoV-2 spike protein genetic information into the body to generate an immune response. These inactivated viruses are changed so they can’t replicate in the body. Unlike AstraZeneca, Sputnik uses two different vector viruses in its two doses.

Does it prevent sickness? The Gamelaya Institute conducted 33,000 person Phase III studies in Russia in September 2020. Preliminary study results showed the vaccine has 91.6% efficacy in preventing symptomatic sickness. As with most of the vaccines approved so far, Sputnik showed 100% efficacy to prevent severe disease.

What does that mean? After getting the second dose of the vaccine, if you get infected with COVID19, the probability of you developing a cough, fever or the major symptoms of the disease is 8.4% and the need to be hospitalised to 0%. 

What about safety? No severe adverse reactions occurred during the study. There were four unrelated deaths during the study (2 already had COVID when they signed up and had self-medicated whilst the other died of a spinal fracture).

What about older people? The study looked for efficacy and safety data in the over 60 population. Although the sample size was small (10%), the efficacy was the same in this group as for the younger ages. 

What about Sputnik in the real world? 3.8 million Russians have received Sputnik since January 2021 and vaccine effectiveness is seen at 97.6% after two doses. No severe adverse reactions have occurred due to the vaccine.

As of May’21, Russia has also now developed Sputnik Lite, a single dose version of its vaccine with a claimed efficacy of 80%. Data is yet to be made publicly available. 

Next up, China’s SinoPharm 🇨🇳

For the longest time, SinoPharm has been that elusive emo kid in a corner at your cousin’s 16th birthday party. Whilst the Sputnik team released its interim reports publicly in the most prestigious medical journal, The Lancet, SinoPharm is yet to release any data directly to the public on its Phase 3 trials.

With the WHO authorisation for emergency use, there was finally some data publicly available. 

What is it? SinoPharm is a 2 dose whole virus vaccine. The whole virus vaccine means an inactivated form of Sars-CoV-2 is used to trigger the body’s immune response. This contrasts with the other vaccines (Pfizer to AstraZeneca to Sputnik), which only uses the genetic information of the spike protein. However, as it’s an inactivated version, it cannot replicate and cause disease in the body. 

As of the time of writing, 45 countries have approved the emergency use of the vaccine, and 65 million doses have been administered globally.

Does it prevent sickness? As per the WHO report, 13,000 people have been enrolled in the trial to assess efficacy, of which only 200 (or 0.01%) were over 60. Vaccine efficacy is at 78.1% in the under 60s with insufficient data to assess the over 60 age group. Studies in the UAE shows efficacy at 86% however further details have not been published.

What does that mean? As per WHO, the probability that you will show symptomatic sickness if you contract COVID19 after being fully vaccinated with SinoPharm is around 22% if you are under the age of 60. WHO cannot tell whether the SinoPharm vaccine will have a protective effect for the over 60s with the data available. 

What about safety? Two severe adverse effects were reported to be possibly linked to the vaccine (serious nausea and inflammatory myelination syndrome). As always it’s a risk-benefit analysis and we should consider the high probability of lung and other organ damage as a result of COVID19 when weighing up any low risks of vaccine adverse effects. 

What about older people? Whilst the study doesn’t provide much data to go on, the post-authorisation use showed 1.1m doses have been given to people over 60 in China. 45 adverse reactions (dizziness, headache, fatigue) were attributed to the vaccine.

Mass vaccinations are one of the few ways we can stop this pandemic from continuing to ravage our lives for years to come. If a vaccination becomes available in your area and after speaking with your doctor about any medical concerns, we recommend getting the jab. It’s not over till we are all vaccinated so even if vaccinated, remember to wear face masks, avoid indoor gatherings, wash hands and stay home!

If you’d like to discuss your vaccination options with a medical professional, our on-demand GPs are available 24/7. Download the oDoc app today.

Sources

  1. Status of COVID19 vaccinations within WHO EUL/PQ Evaluation processes, WHO 
  2. Logunov, D et al., (2020), 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., 397: 671-681
  3. Sputnik, Covid19 Vaccine Tracker
  4. Is Russia’s COVID-19 vaccine safe? Brazil’s veto of Sputnik V sparks lawsuit threat and confusion, Science Magazine (2021)
  5. Efficacy of Sputnik V amounts to 97.6%, TASS (2021)
  6. SinoPharm Evidence Assessment, WHO (2021)
  7. Chinese Covid-19 vaccine has 86% efficacy, UAE says, The Guardian (2020)
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COVID. Quarantine. Isolation. Explained.

COVID. Quarantine. Isolation. Explained.

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COVID, quarantine, isolation are words which we have heard for the last eight months, but do you know what exactly they mean and how they all differ? Let’s take a look. 

 A little background hurts no one

COVID-19 is an infectious disease caused by a group of viruses called coronavirus. Coronavirus means a crown, and it gets its name from its structure. The virus looks like it has a crown around it.

There are many different types of coronaviruses, and they infect a wide range of mammals and birds. Some even cause mild respiratory disease in people every year, so coronaviruses are not new. However, the virus that causes COVID-19 is new. 

SARS-CoV-2 causes COVID-19, and it originated from bats. The virus has been present in bats for a long time, but now the virus has evolved to be able to infect humans and be transmitted between humans. This is the 3rd type of coronavirus that has developed in the same manner. The earlier two coronaviruses caused Middle East Respiratory Syndrome (MERS) in 2012 and Severe Acute Respiratory Syndrome (SARS) in 2003.

Symptoms of COVID-19

Symptoms of COVID-19 include fever, cough, sore throat, tiredness, headache, loss of taste and smell and many others. The combination of symptoms and the severity of them varies from person to person and within regions. The most common symptom seen in patients with COVID-19 is cough, fever and loss of taste. However, most who have the virus may be asymptomatic, showing no symptoms at all and can still infect those around them.

If you are experiencing any of these symptoms call 1390 or use the COVID-19 self-assessment on the oDoc app to understand your symptoms and measures you need to take.  

How does COVID-19 get transmitted so rapidly from one person to the other? 

The virus in infected individuals lives in their respiratory tract, in their mouths, noses, and throats. 

There are two ways transmission of the virus can take place between individuals. 

  • When an infected person speaks, laughs, sneezes or coughs the virus can spread in forms of droplets. This droplet can be inhaled by non-infected people, thereby infecting them.
  • Likewise, the droplets can land and live on surfaces, and when a non-infected person touches these surfaces and then goes on to touch their nose, mouth or eyes, the virus can be transmitted into the non-infected person, thereby infecting them. 

Something to keep in mind is that SARS-CoV-2 is transmitted very easily. So this virus is transmitted between people in ways that make it very difficult to detect and prevent. People are infectious before they have symptoms, so they may be infecting others and not even know it. 

How? 

Keep reading!

The infection – a timeline

Let’s say, on day 1, a person gets infected, and enters the incubation period. 

Incubation period – the time between contracting the virus and starting to show symptoms. An infected person  cannot transmit the disease to others during this period. The incubation period for COVID-19 lasts from 2-14 days with an average of about five days, and then the infected person  enters the infectious period. 

The incubation period for this particular individual lasts 14 days, so they will start showing symptoms on day 14. Day 1 of symptoms  (day 14 of the incubation period in this case) is when they are most infectious. An important thing to note is, even though signs only show itself on day 14, the infectious period begins two days before symptoms show (day 12). 

Infectious period – when the infected person  can transmit the virus to others. The infectious period starts two days before the infected person starts showing symptoms. An infectious person  needs to be isolated, and anyone who comes into contact with them needs to be quarantined. 

The infectiousness of an individual gradually decreases with time. A person is said to be completely free of COVID-19 only when they don’t show any signs of fever for more than 24hrs, and symptoms get better.  In Sri Lanka, a patient is only declared as recovered if the PCR test comes out negative. 

Mild COVID-19 illness can last for about ten days, whereas severe conditions last for more than two weeks. 

Aren’t quarantine and isolation the same thing?

Contrary to popular belief, they are very different. 

When an individual is tested positive for COVID-19, they need to be isolated. This is practised to keep infected individuals away from the healthy population. Isolation period is usually up to 10 days or until signs, and symptoms get better or no sign fever for 24hrs. 

If an individual comes in contact with someone who has tested positive but hasn’t developed any symptoms themselves, they need to be quarantined. This helps prevent spread of disease that can occur before a person knows they are sick or if they are infected with the virus without feeling any symptoms. An individual needs to quarantine themselves for 14 days from the day they came in contact with the positively tested person. 

Suppose you live with a person who has tested positive and is isolating themselves in the same house/ shares communal space with you. In that case, you need to quarantine for the period they are isolating themselves and an additional 14 days from the last day they showed symptoms and signs of COVID-19. 

For example, if your family member tested positive on the 1st of November and recovered on the 14th of November, your quarantine will only end on the 28th of November (14 days from family members recovery). 

The future 

Until a vaccine or treatment for COVID-19 is found and distributed it is up to each one of us to follow safety protocols given by the government to keep ourselves and our local communities safe. Following the DREAM guidelines set out by the government is vital as we slowly resume into normalcy. Adjusting to the new normal may be difficult and frustrating but it is important that we avoid crowded places and gatherings in the near future. It is in our own hands to ensure the safety of ourselves and our loved ones. If you are experiencing any of these symptoms quarantine yourself and call 1390 immediately or use the COVID-19 self-assessment on the oDoc app to understand your symptoms and measures you need to take.

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