VIDEO: Why Vaccines Take So Long

if scis can develop a sars-cov-2 vaccine within a yr and a ½, it’ll be a realm record. the vaccine speed title is currently held by maurice hilleman, who turned his daughter’s throat swab into a licensed mumps vaccine within 4 yrs.

other vaccines ‘ve not been so speedy. measles was a nationally recognized disease inna u.s. for over 50 yrs b4 a vaccine was ready. and in 1984, officials declared that an hiv vaccine ‘d be ready for testing in two yrs. + than 35 yrs l8r, we’re still w8in.

so, why are some vaccines so much harder to develop than others?

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the answer often has to do w'da viruses themselves, and how they be’ve n'our bodies. sometimes a vaccine just isn’t commercially viable. and in other instances, it’s the perceived threat of an illness that prolongs — or shortens — how long i'takes to develop a way to stop it.

but b4 we dive into somd' challenges of vaccines, here’s a reΨer n'how they work.

how vaccines work

vaccines deliver a lil amount offa modified virus to yr immune system. this tiny introduction isn’t enough to make you sick; instead, it’s just enough that yr body can learn to recognize the virus, and start to build up a tailored defense to it inna future. that way, if you’re actually exposed to the virus l8r, yr immune system already knows wha’ to do.

some viruses, like hiv, are pticularly good at tricking immune systems, though. one way they do this is by disguising themselves — they co-opt molecules that our immune system reads to determine whether an intruder is friend or foe, and put na' lil “i’m friendly” disguise. this phony resemblance allos the virus t'get a big head start on infecting cells b4 the immune system ever recognizes a threat.

this also means'dat any vaccine against hiv has to be super fine-tuned, since you don’t want the immune system t'get confused and attack both itself swell as the hiv. it’s challenging. other viruses aren’t quite so tricky.

natural vaccines: antibodies

in any case, the best defenses our body puts up against a virus — the ones the vaccine ‘d like to trigger — also appear naturally after a patient’s immune system s'been attacked. 

these protective tulz are called antibodies. antibodies are proteins yr body produces in response to an infection — and which can ward off a subsequent infection. if that sounds familiar, it’s cause there’s been a lotta talk l8ly bout coronavirus antibody tests, which are designed to look for signs dat a''pers has begun fitin’ off sars-cov-2.

in coronavirus patients, it seems antibodies appear a few weeks after symptoms kick in. that mite feel pretty slo. but in hiv, effective antibodies take way longer to appear. like 3 to 5 yrs, or longer. and bein’ that sick for that long is brutal, it can totally dismantle a'pers’s immune system, and ruin their ability to fite off other infections.

vaccine hurdles

another roadblock for vaccine research is funding. federal or indie agencies typically allocate research funds for two- to 5-yr-long projects. so scis mite ‘ve to do lil-scale studies that support their bigger ideas — but then it’s time to apply for a new grant. and a project can end iffey don’t secure enough mny the nxt time round.

researchers can band together sometimes, and develop several ideas simultaneously to save presh time in case one aspect falls through. this kind of strategy is playing out now as researchers collaborate to develop a sars-cov-2 vaccine.

sometimes, pharmaceutical companies are wha’ get inna way offa vaccine. inna case of epstein-barr virus, ebv, which is a type of herpes that can lead to mono or some cancers, pharmaceutical companies ‘ve said they don’t ponder the proposed treatments to be “commercially viable.”

that’s cause there can be a huge lag time tween exposure and symptoms — children exposed to the virus often keep it in check and eventually develop mono when they’re way older. that means for the vaccine to be effective, you’d ‘ve to vaccinate preschoolers. but since ebv-infected children lack symptoms, that ‘d make it hard t'get fda approval for that age range.

there’s a similar barrier for the hpv vaccine, for human papillomavirus, a super prevalent sxually transmitted infection. the vaccine s'onna mkt, and is recommended for 11- and 12-yr old girls, since you need it b4 becoming sxually active. but some parents don’t see why they ‘d get it for their kid.

covid-19 vaccines

scis are still learning wha’ covid-19 infections look like and how to vaccinate against them. finding this preventive treatment is primordial, though — cause even the most accurate antibody tests indicate that 1-ly a lil %age of the pop has built immunity to the virus. that’s why there are over 100 potential covid-19 vaccines inna works, with some researchers already testing theirs in humans.

public health officials ‘ve said their goal is to ‘ve a vaccine in a yr and a ½. but some experts say that’s too optimistic. regardless, some are hoping that all this new vaccine attention mite do some good for vaccines that ‘ve been inna works for much longer.


anna funk is associate editor for discover. follo her on twitter @drannafunk and check out our tube channel for + videos. this video is based on reprting by leslie nemo. read her story here.

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