The future of non-hormonal birth control: Antibodies can stop sperm in their tracks
Unwanted pregnancy can now be added to the list of preventions that antibodies may be fighting in the near future. For decades, really since the 1980s, engineered monoclonal antibodies have been knocking out invading germs — preventing everything from cancer to COVID. Sperm, which have some of the same properties as germs, may be next.
Not only is there an unmet need on the market for alternatives to hormonal contraceptives, the genesis for the original research was personal for the then 22-year-old scientist who led it. Her findings were used to launch a company that could, within the decade, bring a new kind of contraceptive to the marketplace.
The genesis
It’s Suruchi Shrestha’s research — published in Science Translational Medicine in August 2021 and conducted as part of her dissertation while she was a graduate student at the University of North Carolina at Chapel Hill — that could change the future of contraception for many women worldwide. According to a Guttmacher Institute report, in the U.S. alone, there were 46 million sexually active women of reproductive age (15–49) who did not want to get pregnant in 2018. With the overturning of Roe v. Wade this year, Shrestha’s research could, indeed, be life changing for millions of American women and their families.
Now a scientist with NextVivo, Shrestha is not directly involved in the development of the contraceptive that is based on her research. But, back in 2016 when she was going through her own problems with hormonal contraceptives, she “was very personally invested” in her research project, Shrestha says. She was coping with a long list of negative effects from an implanted hormonal IUD. According to the Mayo Clinic, those can include severe pelvic pain, headaches, acute acne, breast tenderness, irregular bleeding and mood swings. After a year, she had the IUD removed, but it took another full year before all the side effects finally subsided; she also watched her sister suffer the “same tribulations” after trying a hormonal IUD, she says.
For contraceptive use either daily or monthly, Shrestha says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
Shrestha unshelved antibody research that had been sitting idle for decades. It was in the late 80s that scientists in Japan first tried to develop anti-sperm antibodies for contraceptive use. But, 35 years ago, “Antibody production had not been streamlined as it is now, so antibodies were very expensive,” Shrestha explains. So, they shifted away from birth control, opting to focus on developing antibodies for vaccines.
Over the course of the last three decades, different teams of researchers have been working to make the antibody more effective, bringing the cost down, though it’s still expensive, according to Shrestha. For contraceptive use either daily or monthly, she says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
The problem
The problem with contraceptives for women, Shrestha says, is that all but a few of them are hormone-based or have other negative side effects. In fact, some studies and reports show that millions of women risk unintended pregnancy because of medical contraindications with hormone-based contraceptives or to avoid the risks and side effects. While there are about a dozen contraceptive choices for women, there are two for men: the condom, considered 98% effective if used correctly, and vasectomy, 99% effective. Neither of these choices are hormone-based.
On the non-hormonal side for women, there is the diaphragm which is considered only 87 percent effective. It works better with the addition of spermicides — Nonoxynol-9, or N-9 — however, they are detergents; they not only kill the sperm, they also erode the vaginal epithelium. And, there’s the non-hormonal IUD which is 99% effective. However, the IUD needs to be inserted by a medical professional, and it has a number of negative side effects, including painful cramping at a higher frequency and extremely heavy or “abnormal” and unpredictable menstrual flows.
The hormonal version of the IUD, also considered 99% effective, is the one Shrestha used which caused her two years of pain. Of course, there’s the pill, which needs to be taken daily, and the birth control ring which is worn 24/7. Both cause side effects similar to the other hormonal contraceptives on the market. The ring is considered 93% effective mostly because of user error; the pill is considered 99% effective if taken correctly.
“That’s where we saw this opening or gap for women. We want a safe, non-hormonal contraceptive,” Shrestha says. Compounding the lack of good choices, is poor access to quality sex education and family planning information, according to the non-profit Urban Institute. A focus group survey suggested that the sex education women received “often lacked substance, leaving them feeling unprepared to make smart decisions about their sexual health and safety,” wrote the authors of the Urban Institute report. In fact, nearly half (45%, or 2.8 million) of the pregnancies that occur each year in the US are unintended, reports the Guttmacher Institute. Globally the numbers are similar. According to a new report by the United Nations, each year there are 121 million unintended pregnancies, worldwide.
The science
The early work on antibodies as a contraceptive had been inspired by women with infertility. It turns out that 9 to 12 percent of women who are treated for infertility have antibodies that develop naturally and work against sperm. Shrestha was encouraged that the antibodies were specific to the target — sperm — and therefore “very safe to use in women.” She aimed to make the antibodies more stable, more effective and less expensive so they could be more easily manufactured.
Since antibodies tend to stick to things that you tell them to stick to, the idea was, basically, to engineer antibodies to stick to sperm so they would stop swimming. Shrestha and her colleagues took the binding arm of an antibody that they’d isolated from an infertile woman. Then, targeting a unique surface antigen present on human sperm, they engineered a panel of antibodies with as many as six to 10 binding arms — “almost like tongs with prongs on the tongs, that bind the sperm,” explains Shrestha. “We decided to add those grabbers on top of it, behind it. So it went from having two prongs to almost 10. And the whole goal was to have so many arms binding the sperm that it clumps it” into a “dollop,” explains Shrestha, who earned a patent on her research.
Suruchi Shrestha works in the lab with a colleague. In 2016, her research on antibodies for birth control was inspired by her own experience with side effects from an implanted hormonal IUD.
UNC - Chapel Hill
The sperm stays right where it met the antibody, never reaching the egg for fertilization. Eventually, and naturally, “Our vaginal system will just flush it out,” Shrestha explains.
“She showed in her early studies that [she] definitely got the sperm immotile, so they didn't move. And that was a really promising start,” says Jasmine Edelstein, a scientist with an expertise in antibody engineering who was not involved in this research. Shrestha’s team at UNC reproduced the effect in the sheep, notes Edelstein, who works at the startup Be Biopharma. In fact, Shrestha’s anti-sperm antibodies that caused the sperm to agglutinate, or clump together, were 99.9% effective when delivered topically to the sheep’s reproductive tracts.
The future
Going forward, Shrestha thinks the ideal approach would be delivering the antibodies through a vaginal ring. “We want to use it at the source of the spark,” Shrestha says, as opposed to less direct methods, such as taking a pill. The ring would dissolve after one month, she explains, “and then you get another one.”
Engineered to have a long shelf life, the anti-sperm antibody ring could be purchased without a prescription, and women could insert it themselves, without a doctor. “That's our hope, so that it is accessible,” Shrestha says. “Anybody can just go and grab it and not worry about pregnancy or unintended pregnancy.”
Her patented research has been licensed by several biotech companies for clinical trials. A number of Shrestha’s co-authors, including her lab advisor, Sam Lai, have launched a company, Mucommune, to continue developing the contraceptives based on these antibodies.
And, results from a small clinical trial run by researchers at Boston University Chobanian & Avedisian School of Medicine show that a dissolvable vaginal film with antibodies was safe when tested on healthy women of reproductive age. That same group of researchers earlier this year received a $7.2 million grant from the National Institute of Health for further research on monoclonal antibody-based contraceptives, which have also been shown to block transmission of viruses, like HIV.
“As the costs come down, this becomes a more realistic option potentially for women,” says Edelstein. “The impact could be tremendous.”
Angry Citizens Pressure the World Health Organization to Fully Recognize COVID’s Airborne Spread
A new citizen movement is gathering steam to try to convince the influential World Health Organization to change its messaging about how the coronavirus is transmitted.
The new petition "COVID is Airborne" (www.covidisairborne.org) started in early November and has approximately 3,000 signatures. During this particularly dangerous acceleration of the pandemic, the petition's backers allege that the WHO is failing the public with mixed messaging and thus inadvertently fueling the wildfire of transmission.
"Early on in the pandemic, [WHO Director General Dr. Tedros Adhanom Ghebreyesus] said that coronavirus is airborne, but then in March, WHO tweeted that COVID-19 is not airborne, saying that it is primarily transmitted via droplets that are too heavy to hang in the air," says petition co-creator Jessica Bassett Allen.
The organization's late March messaging, still available on social media, is a digital graphic saying, "FACT CHECK: COVID-19 is NOT Airborne".
Screenshot of WHO's Tweet from March 28, 2020 that is still published.
The petition asks for a course correct: "We, citizens of the world, request that the World Health Organization (WHO) recognize the compelling scientific evidence that SARS-CoV-2 spreads by aerosol transmission ("airborne") and urge the WHO to immediately develop and initiate clear recommendations to enable people to protect themselves."
In the vacuum of the WHO's inaction, aerosol scientists around the world scrambled to raise awareness of what they saw as a grave error.
"Almost immediately after that [March 28] announcement, we formed a group of 239 scientists from many countries and disciplines to convince them that they should acknowledge that there is airborne transmission, but we find that they are totally dead set against it," says Dr. Jose Jimenez, a chemistry professor at the University of Colorado at Boulder who has studied aerosols for 20 years. He supports the citizen petition.
In a letter to the WHO back in July, he and his colleagues wrote: "Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1–2 m from an infected individual."
The scientists have also gone direct to the public with their findings: They published a comprehensive Google doc with detailed answers to many people's frequently asked questions about how to protect themselves, addressing issues ranging from the best masks and air filters to how to deal with passing someone outdoors and much more.
It's worth noting that the CDC has now modified its COVID FAQ to include airborne transmission as a "less common way" for the virus to spread. This update took place after the CDC stated in September that it is "possible" the virus spreads via airborne transmission – only to reverse course and remove the language from its website several days later. The CDC's website now states that some viruses, including SARS-Cov-2, "may be able to infect people who are further than 6 feet away from the person who is infected or after that person has left the space."
Basset Allen notes that after the scientists' open letter, the WHO "added ventilation to public communications about how to prevent infection, but they haven't explained why."
When contacted, a WHO representative had no specific comment and shared its late March announcement as well as its latest guidelines on transmission. In part, its statement says, "Current evidence suggests that the main way the virus spreads is by respiratory droplets among people who are in close contact with each other. Aerosol transmission can occur in specific settings, particularly in indoor, crowded and inadequately ventilated spaces, where infected person(s) spend long periods of time with others, such as restaurants, choir practices, fitness classes, nightclubs, offices and/or places of worship. More studies are underway to better understand the conditions in which aerosol transmission is occurring outside of medical facilities where specific medical procedures, called aerosol-generating procedures, are conducted."
A forceful and clear message acknowledging the evidence could make it easier to standardize school and office ventilation, petitioners argue.
Aerosol scientist Jimenez was dismayed by the WHO's response.
"The first part is an error in my opinion," he says. "Current evidence suggests that the main way the virus spreads is inhalation of aerosols.…WHO is way behind, unfortunately.
"The second part is incomplete," Jimenez continues. "Aerosol transmission can happen in those indoor crowded low-ventilation spaces. But if aerosols can accumulate under those conditions and cause infection, they must be extremely infective in close proximity when talking, since they are much more concentrated there. Just like talking close to a smoker you would inhale much more smoke (which is an aerosol) than if you were in the same room, but let's say 10 or 15 feet away."
He adds, "The WHO and others are making the assumption that if this goes through the air, then everyone who is infected is putting a lot of virus into the air at all times, but we know that's wrong: People are infectious for a short period of time before and during their symptoms. In China, they have measured how much virus comes out of people, and they see that the emission is sporadic: The virus can come out in millions of viral [particles] per hour, but it doesn't happen all the time."
The petition's co-creator, Basset Allen, says that her life experience showed her the best way to make a change. "My involvement with this effort is entirely personal," she says. "I was first introduced to HIV treatment activism as a college student and what I learned about campaigning and power has been relevant in almost every other project I've worked on since then. HIV activism taught me that everyday people can win big, life-saving policy changes if they build expertise and work strategically to push decision makers."
The petition and its advocates argue that the WHO's mixed messaging is causing real harm. For instance, a forceful and clear message acknowledging the evidence could make it easier to standardize school and office ventilation, they argue. Anecdotally, some schools have refused to install HEPA filtration in their classrooms due to a lack of specific guidance from health agencies. (Note: The CDC now recommends improving central air filtration and considering the use of portable HEPA filters in classrooms.)
As the holidays approach, a clear and unified message from all influential health agencies would also help people understand why it is still important to wear masks while physical distancing, especially indoors.
"Personally, I cheered when I heard President-Elect Biden mention ventilation upgrades in schools during the first 10 minutes of his October town hall event, and again in the second debate," Basset Allen says. "Unfortunately, we're still more than two months away from the Biden administration taking over the U.S. COVID-19 response and we have to do absolutely everything we can right now to save as many lives as possible. Increasing awareness of airborne transmission and mitigation strategies can't wait. WHO can use its power to help close that gap, here and around the world."
Novel Technologies Could Make Coronavirus Vaccines More Stable for Worldwide Shipping
Ssendi Bosco has long known to fear the rainy season. As deputy health officer of Mubende District, a region in Central Uganda, she is only too aware of the threat that heavy storms can pose to her area's fragile healthcare facilities.
In early October, persistent rain overwhelmed the power generator that supplies electricity to most of the region, causing a blackout for three weeks. The result was that most of Mubende's vaccine supplies against diseases such as tuberculosis, diphtheria, and polio went to waste. "The vaccines need to be constantly refrigerated, so the generator failing means that most of them are now unusable," she says.
This week, the global fight against the coronavirus pandemic received a major boost when Pfizer and their German partner BioNTech released interim results showing that their vaccine has proved more than 90 percent effective at preventing participants in their clinical trial from getting COVID-19.
But while Pfizer has already signed deals to supply the vaccine to the U.S., U.K., Canada, Japan and the European Union, Mubende's recent plight provides an indication of the challenges that distributors will face when attempting to ship a coronavirus vaccine around the globe, particularly to low-income nations.
Experts have estimated that somewhere between 12 billion and 15 billion doses will be needed to immunize the world's population against COVID-19, a staggering scale, and one that has never been attempted before. "The logistics of distributing COVID-19 vaccines have been described as one of the biggest challenges in the history of mankind," says Göran Conradson, managing director of Swedish vaccine manufacturer Ziccum.
But even these estimates do not take into account the potential for vaccine spoilage. Every year, the World Health Organization estimates that over half of the world's vaccines end up being wasted. This happens because vaccines are fragile products. From the moment they are made, to the moment they are administered, they have to be kept within a tightly controlled temperature range. Throughout the entire supply chain – transportation to an airport, the flight to another country, unloaded, distribution via trucks to healthcare facilities, and storage – they must be refrigerated at all times. This is known as the cold chain, and one tiny slip along the way means the vaccines are ruined.
"It's a chain, and any chain is only as strong as its weakest link," says Asel Sartbaeva, a chemist working on vaccine technologies at the University of Bath in the U.K.
For COVID-19, the challenge is even greater because some of the leading vaccine candidates need to be kept at ultracold temperatures. Pfizer's vaccine, for example, must be kept at -70 degrees Celsius, the kind of freezer capabilities rarely found outsides of specialized laboratories. Transporting such a vaccine across North America and Europe will be difficult enough, but supplying it to some of the world's poorest nations in Asia, Africa and South America -- where only 10 percent of healthcare facilities have reliable electricity -- might appear virtually impossible.
But technology may be able to come to the rescue.
Making Vaccines Less Fragile
Just as the world's pharmaceutical companies have been racing against the clock to develop viable COVID-19 vaccine candidates, scientists around the globe have been hastily developing new technologies to try and make vaccines less fragile. Some approaches involve various chemicals that can be added to the vaccine to make them far more resilient to temperature fluctuations during transit, while others focus on insulated storage units that can maintain the vaccine at a certain temperature even if there is a power outage.
Some of these concepts have already been considered for several years, but before COVID-19 there was less of a commercial incentive to bring them to market. "We never felt that there is a need for an investment in this area," explains Sam Kosari, a pharmacist at the University of Canberra, who researches the vaccine cold chain. "Some technologies were developed then to assist with vaccine transport in Africa during Ebola, but since that outbreak was contained, there hasn't been any serious initiative or reward to develop this technology further."
In her laboratory at the University of Bath, Sartbaeva is using silica - the main constituent of sand – to encase the molecular components within a vaccine. Conventional vaccines typically contain protein targets from the virus, which the immune system learns to recognize. However, when they are exposed to temperature changes, these protein structures degrade, and lose their shape, making the vaccine useless. Sartbaeva compares this to how an egg changes its shape and consistency when it is boiled.
When silica is added to a vaccine, it molds to each protein, forming little protective cages around them, and thus preventing them from being affected by temperature changes. "The whole idea is that if we can create a shell around each protein, we can protect it from physically unravelling which is what causes the deactivation of the vaccine," she says.
Other scientists are exploring similar methods of making vaccines more resilient. Researchers at the Jenner Institute at the University of Oxford recently conducted a clinical trial in which they added carbohydrates to a dengue vaccine, to assess whether it became easier to transport.
Both research groups are now hoping to collaborate with the COVID-19 vaccine candidates being developed by AstraZeneca and Imperial College, assuming they become available in 2021.
"It's good we're all working on this big problem, as different methods could work better for different types of COVID-19 vaccines," says Sartbaeva. "I think it will be needed."
Next-Generation Vaccine Technology
While these different technologies could be utilized to try and protect the first wave of COVID-19 vaccines, efforts are also underway to develop completely new methods of vaccination. Much of this research is still in its earliest stages, but it could yield a second generation of COVID-19 vaccine candidates in 2022 and beyond.
"After the first round of mass vaccination, we could well observe regional outbreaks of the disease appearing from time to time in the coming years," says Kosari. "This is the time where new types of vaccines could be helpful."
One novel method being explored by Ziccum and others is dry powder vaccines. The idea is to spray dry the final vaccine into a powder form, where it is more easily preserved and does not require any special cooling while being transported or stored. People then receive the vaccine by inhaling it, rather than having it injected into their bloodstream.
Conradson explains that the concept of dry powder vaccines works on the same principle as dried food products. Because there is no water involved, the vaccine's components are far less affected by temperature changes. "It is actually the water that leads to the destruction of potency of a vaccine when it gets heated," he says. "We're looking to develop a dry powder vaccine for COVID-19 but this will be a second-generation vaccine. At the moment there are more than 200 first-generation candidates, all of which are using conventional technologies due to the timeframe pressures, which I think was the correct decision."
Dry powder COVID-19 vaccines could also be combined with microneedle patches, to allow people to self-administer the vaccine themselves in their own home. Microneedles are miniature needles – measured in millionths of a meter – which are designed to deliver medicines through the skin with minimal pain. So far, they have been used mainly in cosmetic products, but many scientists are working to use them to deliver drugs or vaccines.
At Georgia Institute of Technology in Atlanta, Mark Prausnitz is leading a couple of projects looking at incorporating COVID-19 vaccines into microneedle patches with the hope of running some early-stage clinical trials over the next couple of years. "The advantage is that they maintain the vaccine in a stable, dry state until it dissolves in the skin," he explains.
Prausnitz and others believe that once the first generation of COVID-19 vaccines become available, biotech and pharmaceutical companies will show more interest in adapting their products so they can be used in a dried form or with a microneedle patch. "There is so much pressure to get the COVID vaccine out that right now, vaccine developers are not interested in incorporating a novel delivery method," he says. "That will have to come later, once the pressure is lessened."
The Struggle of Low-Income Nations
For low-income nations, time will only tell whether technological advancements can enable them to access the first wave of licensed COVID-19 vaccines. But reports already suggest that they are in danger of becoming an afterthought in the race to procure vaccine supplies.
While initiatives such as COVAX are attempting to make sure that vaccine access is equitable, high and middle-income countries have already inked deals to secure 3.8 billion doses, with options for another 5 billion. One particularly sobering study by the Duke Global Health Innovation Center has suggested that such hoarding means many low-income nations may not receive a vaccine until 2024.
For Bosco and the residents of Mubende District in Uganda, all they can do is wait. In the meantime, there is a more pressing problem: fixing their generators. "We hope that we can receive a vaccine," she says. "But the biggest problem will be finding ways to safely store it. Right now we cannot keep any medicines or vaccines in the conditions they need, because we don't have the funds to repair our power generators."