How do vaccines approved in Zimbabwe protect us after the first and second shots?

This article was published on
June 25, 2021

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Vaccines don't reach their full effectiveness until a few weeks after the second dose has been administered. Immediate protection after the first shot is not expected to be nearly as protective two to four weeks after the second dose.

Vaccines don't reach their full effectiveness until a few weeks after the second dose has been administered. Immediate protection after the first shot is not expected to be nearly as protective two to four weeks after the second dose.


What our experts say

As of June 24, 2021, the government of Zimbabwe has approved the use of four COVID-19 vaccines:

  • Sinopharm (from China)
  • CoronaVac (from Sinovac in China)
  • Covaxin (from Bharat Biotech in India)
  • Sputnik V (from the Gamaleya Research Institute in Russia)

COVID-19 vaccines tend to begin producing antibodies in people in as little as five days after being administered, but it usually takes a few weeks for the immune system to build up enough protection against the virus to be considered effective.

Each of the vaccine types listed are given in two doses, several weeks apart. They will not reach their full level of effectiveness until a few weeks after the second shot. This means that immediately after the first vaccine dose, protection is not strong and is still being developed. That means it is possible for a person to become infected with the virus during this time.

Different types of vaccines work in different ways, so we do not know exactly how much protection one may receive after one of the four vaccine types in Zimbabwe. We do know that a few weeks after receiving both shots, the risk of severe infections, hospitalizations, and death dramatically decreases amongst people who have been vaccinated.

First doses usually generate immune responses to COVID-19, while the second doses reinforces those immune system reactions. After two shots of a COVID-19 vaccine immune responses tend to be stronger.

There is no evidence to support claims that the COVID-19 vaccine disables or deactivate the immune system while the second reactivates the immune system.

Context and background

COVID-19 cases continue to rise in Zimbabwe on a weekly basis. Roughly 3.9% of the country has been immunized, mostly due to a lack of global supply. With lockdown policies still in effect in some workplaces and quarantines for travelers arriving from certain regions, the government is hoping national stay-at-home measures will help prevent the spread of infections.

Several factors are important to consider for preventing infections with the virus, including the low number of vaccines available, the period of time it takes for both vaccine doses to be given before the body reaches its highest level of protection, which populations will be prioritized during vaccine distribution, how many eligible people opt to take it, whether or not the government will extend the amount of time between the first and second doses, and whether or not booster shots will be needed and given for some vaccine types.

For this reason, vaccines are only a part of puzzle to stop COVID-19. More measures like frequent hand washing, social isolating, and wearing masks are excellent ways to stop the pandemic from impacting more people in the nation and abroad.


  1. Zimbabwe expects 2.5 million Chinese COVID-19 vaccines by month end (Reuters)
  2. Zimbabwe COVAX TA Plan (Gavi)
  3. Zimbabwe (Reuters COVID-19 Tracker)
  4. The Sinopharm COVID-19 vaccine: What you need to know (World Health Organization)
  5. Myths and Facts about COVID-19 Vaccines (United States Centers for Disease Control and Prevention)
  6. Understanding COVID-19 vaccine side effects, why second dose could feel worse (Mayo Clinic)
  7. Five Pressing Questions About COVID-19 Vaccines Answered (EBSCO)
  8. Covovax, Biological E: What we know about India's new Covid-19 vaccines (BBC News)
  9. Zimbabwean government approves four COVID-19 vaccines, two of them Chinese (Xinhuanet)
  10. Is it safe to mix and match COVID-19 vaccines? (Gavi)
  11. Understanding vaccine gaps: What should be the ideal interval between two doses of Covishield? (Firstpost)
  12. COVID-19 India FAQs: Why Do We Need Two Vaccine Doses? Can We Take Different Vaccines for Different Doses? (The Weather Channel/The Times of India)
  13. Why the gap between Covaxin doses has not been extended, Centre explains (Hindustan Times)
  14. How does the Sputnik V COVID-19 vaccine work? (Medical News Today)

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