AstraZeneca Vaccine Gives Sufficient Protection Against UK Variant
By Buddhika Samaraweera
The current SARS-CoV-2 variant, spreading in Sri Lanka, was recently confirmed to be the variant that was first detected in the United Kingdom (UK), following tests conducted on samples obtained from areas such as Colombo, Kurunegala, and Boralesgamuwa.
Heath experts stated the latest variant, is highly contagious and according to them, it is the third variant of SARS-CoV-2 to be detected in the country. According to the health authorities, the country is recording over 1,000 COVID-19 cases on a daily basis, following the detection of the UK variant.
However, Sri Lankans do not yet have a sufficient understanding of this variant and Ceylon Today, therefore, contacted Prof. Suranjith Seneviratne, Professor and Consultant in Clinical Immunology and Allergy at the Royal Free Hospital and University College London, to inquire about some important matters in this connection.
Following are the excerpts of the interview:
What is the UK variant of SARS-CoV-2?
A: The UK variant of SARS- CoV- 2 is called B.1.1.7. This variant was first announced by the UK Health and Social Care Secretary on 14 December 2020. Previous sequencing information found the first positive sample for this variant to be from Kent in September 2020 and the variant is now dominant in much of the UK and has spread to more than 60 countries.
Also, Scientists are uncertain how this variant arose, but similar patterns of mutation have been observed in chronically infected patients with weaker immune systems. It is possible that chronic infection, in a single immune-compromised individual may have led to the origin of this variant.
Is the UK variant more transmissible?
A: Yes, the UK variant is more transmissible. Its transmission increased massively in London and the South East of England during November 2020. Studies suggest the new variant increased the R number by between 0.4 and 0.7. (The R number is the average number of people an infected person infects). If it is above one, the pandemic is growing.
What are the symptoms?
A: Many persons who contract COVID-19 are asymptomatic. Those infected with the UK variant of SARS- CoV- 2 shows similar symptoms to other strains. In a study from England, 35 per cent of those who were tested positive for the UK variant reported to have a cough (compared to 27 per cent who tested positive for other strains).
Other common symptoms include, fatigue (32 per cent of people with the UK variant), muscle aches (25 per cent), fever (21 per cent) and sore throat (21 per cent). Loss of the sense of taste or smell is slightly less common for those infected with the UK variant (15 per cent of persons with the UK variant vs 18 per cent of people with other strains).
Does the UK variant cause more severe disease?
A: Recent studies suggest the UK variant is linked to a higher chance of hospitalisation and death than the original strain. A study of 54,906 persons infected with the UK variant noted 227 deaths (as compared to 141 deaths in those infected with the original strain of SARS- CoV- 2).
It is also observed that a large number of patients infected with this strain have to be hospitalised. It’s a fairly serious situation. This is because having to hospitalise more patients can lead to problems through overcrowding in hospitals.
Is the Oxford-AstraZeneca vaccine effective against it?
A: A study using the Oxford- AstraZeneca vaccine found sufficient protection against the UK variant of SARS-CoV-2. Vaccine effectiveness was 75 per cent against the UK variant when compared to 84 per cent against the initial strain. This level is well above the 50 per cent minimum level of protection recommended by the World Health Organisation (WHO).
Are the Pfizer and Moderna vaccines effective against it?
A: Early laboratory results found the Pfizer/BioNTech vaccine too provides good levels of protection against the UK variant. Similar results were obtained with the Moderna vaccine.
In general, what is the effectiveness of vaccines against this variant?
A: The currently approved COVID-19 vaccines have been shown to be effective against this strain. Vaccination is a very important step in controlling the pandemic, especially since this and other viral variants could cause severe disease.
Usually, blood samples from a person who has been vaccinated is mixed with the virus in the laboratory to see if the vaccine is effective in neutralising the particular virus. But real world effectiveness results are more important to confirm that the vaccinated person is not infected by the circulating virus. There are many real world studies confirming the effectiveness of the COVID-19 vaccines against the UK variant. Therefore, as a whole, all the currently approved vaccines are effective against the UK variant of SARS-CoV-2.
Most people in Sri Lanka have so far received only one dose of the vaccine. What would be its impact?
A: Optimal protection would be received by taking both doses of any two- dose vaccine. However, because of a severe vaccine shortage, the rolling out of the second dose has been delayed not only in Sri Lanka but in many parts of the world. Even then, receiving one dose of the COVID-19 vaccine would provide a significant level of immune protection and is far better than no immune protection at all.
In particular, one dose of the Oxford-AstraZeneca provides 60-75 per cent protection against symptomatic disease. Taking both doses provides about 80-90 per cent protection. Therefore, even a single dose provides a significant level of protection.
In the SIREN study that reported their findings recently, The Pfizer vaccine showed 70 per cent effectiveness, 21 days after the first dose and 85 per cent effectiveness, seven days after the second dose. It was effective against the UK variant that was circulating at the time the persons received this vaccine.
The vaccination process has been shown to be successful and it is an important step for reducing the number of infected patients who have to be hospitalised. Sri Lanka was particularly well in controlling the pandemic compared to other countries. If the vaccination process is carried out only in rich countries and a particular part of the world or community is not vaccinated, the whole world will be adversely affected in the event additional variants not controlled by the vaccines develop.
There are several other variants of SARS-CoV-2 (other than the UK variant) that are spreading in different countries. It is important that all countries and communities be able to gain access to the vaccines in order to provide adequate immune protection. Nine priority groups were identified in the United Kingdom, as those to receive the vaccine first and they have now been vaccinated.
It is also important to be vaccinated in order to prevent serious complications of COVID-19 infection and almost all the approved vaccines that are used at present are showing very high benefit. As I said earlier too, even a single dose of a COVID vaccine can provide significant protection.
How important is it to follow steps such as wearing facemasks and hand washing in relation to this variant?
A: It has been identified that the UK variant can spread very rapidly. In such a situation, wearing facemasks, washing hands and maintaining social distance are very important. All these steps are very important for any COVID-19 variant, and have central importance and necessity with regards to a highly transmissible variant like this.
Especially, by adhering to steps such as wearing facemasks, the viral load that may potentially be transmitted would be reduced. This means that even if the virus is transmitted from one person to another, the viral load would be much less. The spread of the virus should be controlled as much as possible as increased transmission increases the chance of developing more viral variants
It is important to use safety measures such as wearing facemasks both before and after a person gets vaccinated and steps should be taken to educate the public about the benefits of adhering to these instructions and getting the pandemic under control. In particular, benefits such as the ability to return to normal life, a sense of security among others, and the ability to resume activities such as going to school and going to work, should be communicated to the public.
What are the challenges we face in the current situation?
A: In fact, the biggest challenge facing many countries, including Sri Lanka, is to prevent infected and unwell patients needing hospital care and for available hospital capacity to be exceeded, as this would cause so many other problems.
Hospital staff, in particular, may be under extreme pressure due to overcrowding. In addition, health staff, especially Doctors and Nurses would have to take difficult decisions. This is the situation in India at the moment. At a time when there is a lack supply of Oxygen, health staff would have to decide who should be given the available Oxygen. It is undoubtedly a very difficult situation.
We also saw that due to the lack of facilities in some hospitals in India, there were even some conflicts following certain hospitals' refusal to admit patients. Everyone should give their utmost assistance to ensure that such situations do not arise.
Considering the situation, should Sri Lanka go for a lockdown or curfew?
A: Appropriate social distancing and rapid vaccine rollout forms the foundations of getting this pandemic under control. Putting these steps into place would help towards minimising any prolonged lockdowns or closures.
In the early days, Sri Lanka took such steps very well and controlled the spread of the virus. People should be educated and encouraged to follow the appropriate health guidelines at all times.