MBBS(Cey), DCH(Cey), DCH(Eng), MD(Paed), MRCP(UK), FRCP(Edin), FRCP(Lon), FRCPCH(UK), FSLCPaed, FCCP, Hony FRCPCH(UK), Hony. FCGP(SL)

Specialist Consultant Paediatrician and Honorary Senior Fellow, Postgraduate Institute of Medicine, University of Colombo, Sri Lanka.

I have written several articles in The Island about the COVID vaccine in the very recent past, where I discussed some important bits of information. This present effort is undertaken to provide some additional details regarding the current state-of-play in this vitally important endeavour, geared towards winning the war against this tiny, but unbelievably powerful blight of a coronavirus.

The vaccine is here now, in our land, albeit in rather limited quantities and, up to the present time, it has arrived in about three tranches or batches. What we have got down, is the Oxford-AstraZeneca viral vector type of vaccine. It uses an inactivated chimpanzee adenovirus as just a vehicle to get a component of the SARS-CoV-2 virus that causes the COVID-19 disease, into the human body. This component then induces an immunological reaction in the recipient that induces the immune system of the body to recognise the spike protein of the virus, and mount an immunological reaction against it by producing antibodies. The spikes of the coronavirus are the all-important components that enable the virus to attach itself to human cells, particularly of the respiratory tract. The vaccine also induces the immunological system to develop antigenic memory where in any subsequent infection by the virus, the cells of the immune system react and produce antibodies to neutralise the coronavirus that causes COVID-19 disease. A second dose of the vaccine enhances the immunological capabilities of the body so that an immediate and sustained attack could be initiated quite rapidly, if and when the body is exposed to the pandemic virus.

The currently available vaccine in Sri Lanka was rolled out in the country from about mid-January, or so, this year. It was initially given to all frontline healthcare workers, the tri-forces and the police personnel who were involved in patient care, tracing of contacts and running the quarantine facilities. All these people belonged to a high-risk group who needed to be protected at all cost. Following the first dose, the recipients were requested to come back in four weeks for the second dose to complete the initial vaccination process. This procedure of administering the second dose was scheduled for the four-week period because the original clinical trials of all vaccines, except the single dose Johnson and Johnson vaccine, however were carried out with this time schedule. The studies showed a reasonable degree of protection from about 12 to 14 days after the initial dose. Following the initial vaccination efforts, some other age groups were also vaccinated, the efforts at this being dictated to by the resources available and the logistics that could be mustered. There was a huge demand for the vaccine but, unfortunately, the supplies were limited and certainly not quite sufficient to meet all the needs. To complicate matters further, ad hoc decisions were also made and some of the science-dictated priority lists were disregarded to a certain extent, perhaps for just a few days.

Then it was vaguely intimated that the second dose was going to be delayed to around three months after the first dose. Unfortunately, no proper communication as to the scientific reasons for this abrupt change in the timing schedule was conveyed to the general public and they were left wondering as to why this was done. Some thought that there was something wrong with the vaccine while others thought that the authorities were not able to get sufficient stocks of the vaccine to administer the second dose after four weeks. Many others smelled a rat in that entire endeavour.

In point of fact, there are some valid scientific reasons for changing the schedule. Once the vaccine was rolled out in other countries, especially in Europe and particularly so in the United Kingdom, continuing scientific assessments made it clear that the initial protection to a degree of around 60% was quite robust and was even extended to a period of more than three months. There was also some suggestion that by delaying the second dose, one might even get a stronger immune response and a more prolonged period of protection. Although opinions were divided, the United Kingdom went ahead and changed the schedule to have the second dose administered after three months. A secondary reason for extending the time interval was that as the supplies were sparse even in the UK. The positive benefit was that it was possible to give the first dose to a larger number of people, thereby increasing the total number of people who would have some immunity. There were protests even from some doctors in the UK that the authorities were going against science as the clinical trials of the vaccines had used the four-week time interval originally. Yet for all that it must be remembered that science could and does change with the unravelling of new data and that the decision that was taken by the authorities in the UK was based on sound public health principles. The advantages of protecting a larger group of people of a populace with the first dose of the vaccine is also scientifically tenable in a potentially lethal disease.

All these principles are also quite tenable and should be acceptable in the Sri Lankan scenario. But the down side of it all is that nobody came over the mass media to explain the reasons for the decision that was made to change the time schedule. It is absolutely imperative that we keep the public properly informed, mainly to prevent all kinds of unsubstantiated “devil’s playground” type of canards spreading around like wildfire and initiating as well as propagating public panic.

All clinical trials have shown up the vaccine to be quite effective and safe apart from mild side effects during the first 48 hours or so after the administration of the vaccine. These were very well documented as chills (feeling cold), fever and body aches. All these respond quite well to simple pain-killers such as paracetamol. Generally, both here and abroad, these side-effects have not led to any cause for alarm.

However, over the last week or so, there are disturbing reports of more serious problems that have occurred in certain countries in Europe. These have been reported and generally even sensationalised by all types of media. The general public of our country must be getting really worried about these latest developments as regards the vaccine. These worrying effects seem to have occurred predominantly, although not exclusively, after the second dose of the vaccine and have been reported with the Oxford-AstraZenica vaccine. These undesirable effects consist primarily of documented cases of unexplained clotting of blood in deep veins with, in some cases, the clots being detached and getting deposited in the blood vessels of the lungs. There has been a couple of deaths as a result of the clots getting deposited in the lung arteries, a condition known as pulmonary embolism. As a result of these initial reports, many European countries have temporarily suspended the administration of the Oxford-AstraZenica vaccine till more intensive investigations are carried out to ascertain a definitive cause-and-effect relationship.

At the present time, there is no direct evidence as to whether the problem was definitely caused by the vaccine. We do not know whether the affected individuals had a coexistent abnormality in clotting of blood. These clotting problems in deep veins are more common in the European countries anyway. Though seen from time to time, these deep vein thrombosis problems are quite rare in tropical countries, especially in Sri Lanka. It is generally seen here after major surgery where mobility of the patient had been severely curtailed and clotting occurs in the deep veins of the legs. The increased tendency for clotting of blood in deep veins may also be related to the use of certain other medications such as oral contraceptive drugs, which are used a lot more in the European countries and in the Western hemisphere of the world. The message that we should convey to the public is that THERE IS NO CAUSE FOR UNDUE ALARM AND PANIC in our country regarding this problem at the present time. The position would be clearer within the next few weeks when these cases are thoroughly investigated. For the time being at least, there are no grounds for suspending the administration of the Oxford-AstraZenica vaccine in our country.

Initially, all the clinical trials indicated that the vaccine was capable of reducing the severity of the disease and would thereby reduce deaths. That was the primary reason for the use of the vaccine. However, there seems to be some accumulating evidence now that it would reduce the ability of the virus to infect humans as well, at least to a certain extent. There is some evidence that even if the vaccinated subject gets infected, the number of virus particles in the body may be reduced by a considerable extent. Although all these findings imply that this is not a complete or one hundred percent protection against being infected, the implication of this is that it could perhaps reduce transmission of the virus from infected people to those uninfected. In a new scientific paper published in a pre-print journal on the 01^st of

February 2021, the researchers found that the vaccine cut the number of cases with detectable virus by 67% after a single standard dose, and wrote that this shows the potential for a substantial reduction in transmission.

From a public health perspective that is an added bonus. If sufficient herd immunity could be instituted by widespread use of this vaccine, then the rate of spread could also be reduced and then the pandemic could be controlled. It would also serve the main purpose of reducing the severity of symptoms and thereby reduce the all-important deaths while reducing the need for high-powered intensive care for those who become symptomatic.

As so graphically pointed out by Dr Tedros Ghebreyesus, the Director General of the World Health Organisation (WHO) and reproduced verbatim here, “This is a time for facts, not fear. This is a time for rationality, not rumours. This is a time for solidarity, not stigma“. These are indeed a set of golden words for our populace as well as for the powers-that-be in our paradise isle. We are learning a lot about this coronavirus and the pandemic virtually daily. We need to explore windows of opportunities and change our strategies according to the scientific details that would be unravelled.

Yet for all that, all of us…, every single one of us, need to still comply very strictly with the all-important health recommendations of the 3Ws…, Wearing a mask; Washing of hands and Watching out for the maintenance of the physical distance of at least one to one and a half metres. The vaccines do not give us unabridged permission to abandon these public health measures towards controlling the pandemic. There is no way in which the observance of these measures could be put aside at the present time. By all means, get the vaccine when it is made available to you but even after that, do abide by the health guidelines. That will be your humble but priceless contribution towards saving lives.