The mass production of the COVID-19 vaccines has been nothing short of a feat of medical science, and the rollout across many countries has been incredible. But there is a fly in the ointment – two, to be precise: How long does the protection provided by a vaccine last? And, will the vaccines be effective against emerging variants?
The tragic situation unfolding in India is a case in point when it comes to fighting new variants of the coronavirus. India has a population of 1.4 billion and had an excellent start to its vaccination programme. It is also home to one of the biggest manufacturers of vaccines in the world: the Serum Institute of India (SII), which was making and exporting millions of vaccines to other countries as cases were coming down in India.
But due to recent public gatherings, and the early easing of lockdown measures, India has found itself at the epicentre of the pandemic, setting global records for daily cases and deaths. The world has watched in horror as scenes of people struggling to breathe outside hospitals have streamed across news networks.
The SII and the Indian government have now reduced the volume of vaccine being exported from India, but this has come too late as they are also struggling to obtain the raw materials needed for vaccine manufacture from the United States, which is focused on getting its own population vaccinated.
This highlights the problem of Western countries prioritising their own vaccinations while other countries miss out. It also shines a light on holes in the World Health Organization’s plans to get vaccines to poorer countries through its COVAX scheme. As the pandemic unfolds, it is becoming clearer that there are likely to be huge outbreaks in some countries, and a global firefighting approach will most likely be needed. India is one of the world’s fastest growing economies, but the pandemic has brought it to its knees, forced to ask for foreign aid.
The longer the virus is able to run riot in India, the more people it will infect and the more likely it is that further mutations will emerge.
Scientists believe the latest Indian “double mutant” variant exhibit traits that could make it more infectious and less susceptible to vaccine-induced immunity, and we may well see the virus mutate further and in a direction that will make the current batch of vaccines even less effective.
As new variants emerge, therefore, we are likely to need booster shots to maintain our levels of protection or to fight new variants.
How long does protection from a COVID vaccine last?
Another issue is that we do not know for sure how long protection lasts after having a COVID-19 vaccine. Most experts agree that protection is likely to last at least six months but only time will tell and further research is needed.
According to a study of 927 people, conducted by Pfizer and published on April 1, 2021, the vaccine offered 91.3 percent protection against COVID-19, measured from seven days through to six months after the second dose.
The company is also conducting a study into the effectiveness of a third dose of the vaccine – essentially a booster, given six to 12 months after the second dose. The study is part of Pfizer’s clinical development strategy to determine the effectiveness of a third dose of the same vaccine against evolving variants.
A study looking at the length of time the Moderna vaccine gives protection also showed those people who were given two doses of the vaccine had good antibody levels at six months after the second dose.
There is less data available for the Oxford-AstraZeneca vaccine. However, when looking at the effectiveness of the vaccine after giving the two doses at different intervals, studies have shown that the vaccine efficacy reached 82.4 percent after a second dose for those who had a dosing interval of 12 weeks or more, meaning if the two doses are given at least three months apart they offer more than 82 percent protection. It is therefore reasonable to think the protection will last at least a further three months after the second dose, although more data is needed.
It is entirely possible that vaccine-induced protection will last longer than the six months being proposed by these findings, but many experts believe that the antibodies created by vaccines will wane over time and booster shots will be required.
How will boosters work?
Booster shots work like a wake-up call for your immune system. Vaccines stimulate the body to create antibodies that are capable of recognising the coronavirus and, should you encounter it, killing it and any cells that have been infected by it, usually before you develop any symptoms.
Once this is complete, memory T and B immune cells patrol the body in case another encounter occurs. Over time, the numbers of these memory cells start to dwindle and the immune system may “forget” how to recognise the pathogen or germ causing the illness effectively in the future.
Booster shots serve to “remind” the immune system how to recognise the specific pathogen causing the disease. It means your body is more likely to respond quickly and more effectively after a booster shot.
According to Albert Bourla, the chief executive at Pfizer, the answer to whether we will need booster shots is “yes”. Speaking with American healthcare company CVS Health on April 16, Bourla said: “There will be likely a need for a third dose somewhere between six and 12 months [following the first two doses] and then from there, there will be an annual revaccination.”
Nadhim Zahawi, the UK’s vaccine minister, has said people who are clinically extremely vulnerable could begin to receive booster shots against new coronavirus variants as early as September. And David Kessler, chief science officer to the White House coronavirus task force, spoke to a congressional committee in the US about the need for booster shots, saying: “We understand that at a certain point in time we need to boost, whether that’s nine months, 12 months, and we are preparing for that coming.”
Booster shots are not a new phenomenon; we use them for other vaccines. We give booster shots of the measles, mumps, rubella (MMR) vaccine to children to ensure longer lasting and effective immunity and we give annual flu vaccines to clinically vulnerable people to protect against new strains of the flu virus.
Can boosters protect us from new variants?
New variants of the coronavirus are emerging all over the world. Only a handful are “variants of concern” – those that may harbour mutations enabling them to evade our immune responses triggered by vaccines. Booster shots may also serve as a way to stimulate the body to recognise new variants of the coronavirus as well.
Variants of concern include the South African, Brazil and Indian variants which have emerged in recent months (the vaccines appear to be effective against the UK variant). These variants include mutations of the spike protein (the part of the virus that binds to human cells) which might make them harder to recognise by immune cells generated by vaccines.
If these variants become dominant variants or more widespread then booster shots which can protect us against them are likely to be needed. If vaccines do need to be tweaked to be more effective against new variants, manufacturers have said that these will be easy to do and can be done in less than three months.
As time goes on, it is looking more and more likely that booster shots against COVID-19 are going to be needed. Many people argue that there is going to be a never-ending cycle of vaccines and boosters, but we already tolerate this with flu each year and we should start to look at vaccines against the coronavirus as no different to that.
Progress report: A possible vaccine for malaria
Another serious disease that kills some 400,000 people every year is malaria. But, at last, there may be a solution in sight. On April 23, researchers from the University of Oxford and its partners announced some promising results from tests of its vaccine which they claim is 77 percent effective in preventing malaria – higher than the World Health Organization (WHO) target efficacy of 75 percent.
Malaria is a deadly disease. The majority of deaths from malaria each year occur in Africa and children are worst affected. Malaria is caused by a family of parasites called plasmodium. These parasites are transmitted to humans by female mosquitoes (the males do not tend to feed on blood).
Female mosquitoes bite humans to feed on blood and, in doing so, transmit the parasite to them. By far the most common type of malaria parasite is called plasmodium falciparum which accounts for more than 99 percent of cases in Africa.
The symptoms of malaria include fever, headache, chills, anaemia and respiratory distress. Untreated, the parasites can destroy human red blood cells, cause organs to fail and eventually lead to death. Despite measures such as mosquito nets, insecticides and antimalarial drugs being available, many poorer regions continue to have high mortality rates from malaria, especially among children.
After the first exposure to malaria, some level of immunity is acquired so when an individual is infected again they have fewer symptoms. However, this immunity requires regular exposure to malaria through bites so if a person leaves an area where the disease is endemic and then returns again, their immune system may have “forgotten” how to fight malaria and they can get severe symptoms again.
Many pharmaceutical companies have attempted to come up with a malaria vaccine in the past but have fallen short of the 75 percent efficacy rate recommended by the WHO, which is why this latest news is a reason to celebrate.
The researchers have published their phase 2b clinical trials in The Lancet. The study examined 450 children aged between five months and 17 months across 24 villages in the Nanoro region of Burkina Faso in West Africa. The children were randomly split into three groups: the first group was given the new malaria vaccine – known as R21/Matrix-M – at a high dose; the second group received the same malaria vaccine but at a lower dose; and the final group received a “control” rabies vaccine.
Doses were administered from early May 2019 to early August 2019, largely prior to the peak malaria season in the region. The researchers have now reported a vaccine efficacy of 77 percent in the higher-dose group and 71 percent in the lower dose group. Importantly, no serious side effects from the vaccine were found during the trial.
The study will now move to the all-important phase 3 part of the trial, for which 4,800 children, aged five months to 36 months, across four African countries, will be recruited. If this study shows the same levels of efficacy and safety as the phase 2b trials, but on a larger scale, then the hope is that we will have an effective malaria vaccine we can use to protect at-risk populations and hundreds of thousands of lives will be saved. The team has partnered with the Serum Institute of India to manufacture at least 200 million doses annually in the coming years, should the phase 3 trials go well – there is no indication as yet when this might start.
Gareth Jenkins, of Malaria No More UK, said in response to the vaccine news: “A world without malaria is a world safer both for the children who would otherwise be killed by this disease, and for us here at home. Countries freed from the malaria burden will be much better equipped to fight off new disease threats when they inevitably emerge in the future.”
In the Doctor’s Surgery: Supporting families through a funeral during the pandemic
When my father passed away more than 10 years ago, it was an incredibly difficult time for the whole family. Community support is central to South Asian culture, both in times of celebration and, more importantly, in times of grief. Within an hour of his death, news of my father’s passing had spread among my parents’ friends and people came to our home to show their support.
My mum depended on these people; they would turn up with dishes filled with food so we did not have to cook, they would make endless cups of tea for the mourners who visited, they would clean up after guests left so we were not left with that job and they would sit and recite verses from the Quran which offered my mum some comfort. For me, it meant I could get on with the practical job of arranging the funeral, knowing my mum was being looked after by the community.
This past year has seen our community and others like it robbed of these small but important gestures. COVID has put an end to large gatherings in many countries and numbers at funerals have been severely restricted. This was never more apparent than at the recent royal funeral in the UK when the queen was seen sitting alone during the service for her late husband, Prince Phillip.
As a family doctor, I speak to people who have lost loved ones more often than I would like. The pandemic has meant I do this even more frequently than ever before, offering my support and advice when needed but more often just listening to how they are feeling.
Although my patients fully understand the need for restrictions in order to curb the spread of the virus, they often tell me how this has adversely affected their period of grieving. One man told me: “We believe the more people who turn up at your funeral and pray for you, the more blessings you have when you arrive at the gates of heaven. My mother only had 30 people at her funeral and none of them was able to come back to our home afterwards. It was heartbreaking.”
I tried to reassure him that although people could not visit, they could quietly pray for her in their own homes if that was what the family wanted.
More recently, a husband who was distraught after losing his wife to COVID said to me: “Her parents [who lived in Pakistan] cannot even attend her funeral. Imagine what that must feel like to them.”
People expect doctors to have an answer to every situation but I did not have an answer to that.
Losing a loved one is hard enough when we were not living through a pandemic, but almost every culture across the world relies on communities, friends and families to come together in times of grief to share the burden and to help ease the pain. I worry that, for my patients, this lack of physical human support will only serve to prolong their grief and will have an untold negative effect on their mental health.
And now some good news: Could a COVID-19 pill be available soon?
The UK government has announced that an Antivirals Taskforce is to be set up for the trial of medication that could be used to treat COVID-19 at home for those not sick enough to need hospitalisation.
The hope is that this anti-viral treatment could shorten the illness and reduce the risk of spreading the illness to others. The drugs may also be given to close contacts of someone who has tested positive to help contain an outbreak.
One drug being touted as a contender is the Pfizer-produced PF-07321332, a drug that has shown to reduce viral replication in laboratory studies. Another drug being studied is the anti-viral medication, molnupiravir, which was originally developed to treat SARS and MERS. So far, this medication has been shown to be effective in reducing viral replication in animal tests and is currently being tested in humans.
So far, we have had limited success with antiviral medication, but this may change as further research is carried out. If successful, the medication could be used worldwide to manage patient care at home and reduce deaths. It may be particularly useful for people who are unable to have the COVID vaccines due to medical reasons.
Reader’s question: I have had my first dose of the AstraZeneca vaccine, but I am now worried about blood clots. Can I request an alternative vaccine for my second dose?
While studies are continuing as to whether mixing doses of vaccines will offer better or worse protection, there are no results as of yet, meaning we would not currently advocate mixing doses of different vaccines. Most health authorities agree that the benefits of having the AstraZeneca vaccine outweigh the risks, particularly in those above 30 years of age. The risk of developing blood clots from being infected by COVID itself is significantly higher than the risk associated with the AstraZeneca vaccine.
My advice is to take up the vaccine that is offered to you whatever brand it is – it will offer you protection against serious illness from COVID-19.