The world’s media have gone into excited overdrive over the last couple of days with the announcement that US drug company Pfizer has developed an effective vaccine against Covid-19. Should we be celebrating? Or is our desperation for a vaccine and a ‘return to normal’ clouding our collective judgement?
The word ‘vaccination’ comes from ‘vacca’, Latin for cow. It’s a term derived by English scientist Edward Jenner. In the eighteenth century, it had already been observed that milkmaids rarely caught smallpox. They did however get a mild illness after milking cows infected with cowpox, causing skin blisters but no serious or lasting symptoms. Jenner took pus from the blisters of Sarah Nelmes, who caught the disease from a cow named Blossom. He then scraped the pus into the skin of eight-year-old James Phipps, the son of Jenner’s gardener. The boy developed mild symptoms, but nothing serious. He then exposed the boy to several smallpox patients, but the boy seemed to be protected. Bearing in mind that smallpox is an extremely virulent disease with a death rate of 30%, Jenner’s ethics were to say the least questionable, and a reflection of class politics of the time. But he went on to vaccinate around 30 other people (all, we presume, servants or the offspring of servants) with the same result: apparent immunity from smallpox. We now know that cowpox is caused by a virus that is in effect a much less virulent form of the smallpox virus, which has the same proteins on its protective coating as smallpox, and so stimulates the production of antibodies that are effective against smallpox. And so the principle of vaccination to create immunity was established.
Since then, this basic principle developed by Jenner has been used to create many effective vaccines, saving millions of lives, and virtually eliminating deaths from childhood killers such as polio, whooping cough, and TB, at least in developed countries. To make these conventional vaccines, we take bits of dead or attenuated (ie nearly dead) virus and inject it into an animal, provoking the animal to produce antibodies to the protein components of the virus, otherwise known as viral antigens. When the animal is infected with the live virus, it already has high levels of antibodies that can attack and neutralise the virus before it results in a serious infection.
The Covid-19 vaccine that Pfizer has developed is a m-RNA vaccine. That’s a relatively new type of vaccine. Although other m-RNA vaccines have been developed against other viruses, they’re not yet in general use. These vaccines work differently from conventional vaccines. Rather than injecting bits of virus into an animal, we borrow a trick from the virus itself and recruit the animal’s cellular machinery to make the viral proteins in the same way that the virus would. This is done by using messenger RNA (m-RNA), a molecule that plays an important function in our cells. Our m-RNA copies the genetic code on the DNA in our cell’s nucleus, and takes it to ribosomes in our cell’s cytoplasm – that is, the bit of the cell outside the nucleus. These ribosomes are protein factories, and make proteins from amino acids floating around in the cell. The order these amino acids are joined together to make a specific protein is determined by the genetic code carried to the ribosome by the m-RNA molecules. These new m-RNA vaccines work by creating completely synthetic m-RNA that gets into the animal’s cells, and programmes the ribosomes to make bits of viral protein. In the case of this new Pfizer vaccine, they make the spike proteins that form the ‘halo’ around the virus. These spike proteins are quickly recognised by white blood cells as ‘foreign’, provoking them to make antibodies that will also recognise and attack the same protein on actual Covid-19 if and when you’re infected.
It’s brilliantly ingenious, and represents a level of bioengineering that could only have been dreamed of when I was studying microbiology. It’s also easier and quicker to produce the vaccine, because the m-RNA is entirely synthetic, and doesn’t require large quantities of Covid-19 to be grown in cell cultures and broken up or attenuated as in a conventional vaccine. And there’s no chance of Covid-19 infection from the vaccine, as no actual virus is involved in the process of creating immunity.
So what’s not to like about this? Well, nothing – if it works. However, it’s worth looking at the figures behind the Pfizer trials for the vaccine. The large-scale trial involved 45,000 people, half of whom received the trial vaccine, and half of whom received a placebo (probably a vaccine to a different virus). However, in total, across both groups, only 94 cases of Covid-19 were detected. True, 90 percent of these were in the control group and only ten percent in the vaccinated group, but those are very low numbers to be statistically meaningful. To put it bluntly, they’re not. And of course, we’ve no idea how long immunity conferred by the vaccine will last, the trial simply hasn’t gone on long enough to make any judgements on that. It is encouraging though that from the entire trial, no significant adverse reactions to the vaccine were noticed, as you would hope for a m-RNA vaccine.
This very low infection rate is a little odd. The trials were carried out across several countries, different ethnic groups, and different ages. Even in the control group, only 0.4% were infected. That’s low, when you consider that at the time of writing this, more than double that percentage of the UK population are infected, according to estimates from the Imperial College ZOE study. This could be because people who volunteered for the vaccine trials are more aware of the virus, and are more cautious about protecting themselves from it. Just because you’re in the trial, you’re not going to be enthusiastic about catching the virus, particularly as there’s a 50-50 chance you were injected with a placebo.
These very small numbers mean it’s impossible to make any judgements about how effective the vaccine is at protecting people in different age groups, different ethnic backgrounds, or even between men and women – the numbers are just too small. So while the results are promising, the numbers at this stage can’t possibly reveal for certain whether the vaccine really will be 90% effective as Pfizer have claimed, nor which groups it will protect effectively. Not unexpectedly, Pfizer’s share prices shot up with the vaccine announcement, but have since dropped back significantly, possibly as investors realise what the trial ‘success’ figures actually mean.
There are practical problems with the Pfizer vaccine however. It has to be stored at -80 degrees, within a couple of days of its use. To use it on a large scale would require significant investment in specialist ‘ultra low freezers’ and ‘cold chain’ facilities needed to store and transport it – domestic and industrial deep freezers usually operate down to only -20 degrees. Healthcare providers in some countries might prefer to wait a little longer for a reliable vaccine that doesn’t require this big additional infrastructure investment. Other vaccines, such as the one being developed by Oxford University, can be stored at room temperature, and are close to being released for general use. The Oxford vaccine is a conventional vaccine, deriving immunity from a chimpanzee virus similar to Covid-19, so not unlike the very first smallpox vaccine developed by Edward Jenner. Trials of this vaccine have indicated that it is effective in older people.
It’s also worth looking at Pfizer as a company, and their track record. Pfizer are a huge multinational, the epitome of ‘big pharma’. They are a major employer of political lobbyists. Last year, they spent $11,000,000 on lobbying in the US, and $25,000,000 back in 2010. Much of their lobbying has been around health care reform, arguably as ‘good guys’ promoting universal free healthcare and supporting Obamacare. But of course, that’s coupled with making sure that drug prices aren’t capped. Pfizer make no secret that their lobbying is out of self-interest. Their own website says that they employ lobbyists in ‘the interests of our company, shareholders, employees, and other stakeholders’. No mention of any public interest, but then this is a US multinational we’re talking about, and this is how capitalism works. Some of their lobbying has been a bit more questionable, however. According to US State Department cables released on Wikileaks, Pfizer ‘lobbied against New Zealand getting a free trade deal with the US because it objected to New Zealand’s restrictive drug-buying rules and tried to get rid of New Zealand’s health minister Helen Clark’. So they’re apparently not above interfering in the democratic procedures of other countries to serve their own interests.
What we’re looking at here with the roll-out of this vaccine is, in effect, an extension of the vaccine trial on a scale big enough to get meaningful data. It’s just that Pfizer are now expecting governments to pay them to participate. Would I get vaccinated? Yes, I would. It seems unlikely that a m-RNA vaccine could be harmful, and there’s a good chance it will offer protection from Covid-19. But I’d continue to be cautious and avoid any infection risk, until a lot more data has been gathered.
Call me a cynical old socialist, but I would tend to have more faith in the Oxford University trial. Not because it’s British, nor because the trial size is any bigger (it isn’t). It’s just that if it’s led by an academic institution it’s more likely to be driven by interests shaped around the public good, rather than huge profits for American multinationals. And it won’t require the cold chain infrastructure.
But overall, all this is still good news. Whether you believe in the power of profit-driven capitalism to come up with a way out of the Covid crisis or the power of collective human endeavour for the public good, it seems we are now very close to an effective vaccine. It’s just that I don’t believe we can say for certain that we’re there yet.